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The Best Boat Trailer Locks

Written by Anthony Roberts / Fact checked by Jonathan Larson

Trailers are easy to steal and sell, making them a common target among thieves. Using the best boat trailer lock is a great deterrent. It adds a layer of security for peace of mind. I am at ease leaving my trailer knowing that it stays safe.

best boat trailer lock

It should be a difficult task in choosing boat trailer locking devices. Otherwise, it is useless in securing a trailer. More so, consider what suits the size and type of the trailer that you have, especially the hitch. Go beyond the price of the lock as you decide which one to pick.

I am here to make things easy for you! This buying guide walks you through the top locks for boat trailers. I will also share some important buying considerations and answer a few questions you might have about trailer locks.

<strong>Top 1</strong>

Master Lock 389DAT

+ Easy to install and remov
+ Has a universal coupler compatibility
+ Comes with a limited lifetime warranty

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<strong>Top 2</strong>

Reese Towpower 72783

+ Bright body easily deters thieves
+ Wide range of compatibility on different couplers
+ Customizable ratchet that allows 11 positions

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<strong>Top 3</strong>

Shoreline Marine Lock

+ A good choice for budget-conscious buyers
+ Made of corrosion-resistant steel
+ Screw-type locking mechanism for a secure fit

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Top 12 Boat Trailer Lock Reviews

1. Master Lock 389DAT Trailer Lock

With thousands of reviews from satisfied customers, this boat trailer hitch lock guarantees the highest level of satisfaction. It has a sturdy construction, ensuring rust and corrosion resistance. It endures harsh outdoor elements. I also love the bright and attractive red finish. It is affordable and durable as well!

The versatility of this trailer lock is also worth noting. With its universal design, it fits most couplers. I can use it at a maximum of 2-5/16” coupler, which is the most common size available. From small to large couplers, this lock promises superior performance.

This trailer lock is designed for ease of installation and removal. It is unlike others that are prone to be stuck. It has a smooth mechanism with a sliding ball that also makes the lock more reliable even after years of use. I find them easier to use than traditional hook-style locks, which can be difficult to undo, especially when it is cold.

I am confident that you will stay happy even after years of use because it has a limited lifetime warranty. The manufacturer offers free repair or replacement if the lock shows problems in workmanship at any point of its use.

One potential problem in this lock is the sharp edges, which can scrape the hitch. This contact results in the peeling of paint, which turns into an eyesore. Also, when you are using it in a larger coupler, expect that there is a bit of wiggle unlike how tight the fit is in a smaller coupler.
  • Sturdy construction resists rust and corrosion
  • Easy to install and remove
  • Has a universal coupler compatibility
  • Comes with a limited lifetime warranty
  • Lock scrapes paint on the hitch
  • Wiggles when attached on larger couplers
From its bright red finish to a limited lifetime warranty, this long-lasting trailer lock is one of my favorites! So you should consider getting this trailer lock.

2. Reese Towpower 72783 Universal Coupler Lock

Constructed with a premium steel bar, this boat trailer coupler lock guarantees durability. I like how it has an advanced locking mechanism to resist prying and drilling. The bright yellow color is a good thing, making it an effective visual deterrent against thieves.

The most reliable boat security locks are those that accommodate a wide range of couplers. Luckily, this item fits three of the most common coupler sizes. I also love how the lock has a customizable ratchet with choices of up to 11 positions. This feature makes the lock versatile to be used in different sizes and designs of trailer hitches.

The package is inclusive of two keys. While there are duplicates of the keys, it is available in several versions. This means that there is a minimal likelihood that someone in your area has the same design of the key that you have. The key fits smoothly, making it effortless to release the lock bar.

However, take note that this coupler lock has an aluminum body. While it is lightweight, it is not as sturdy as its steel counterparts, making it easily prone to damages. Make sure to handle it with care. Also, if the trailer hitch has a tongue width of more than four inches, this lock does not work.
  • Bright body easily deters thieves
  • Wide range of compatibility on different couplers
  • Customizable ratchet that allows 11 positions
  • Has two keys that fit easily and smoothly
  • Aluminum body can be easily prone to damages
  • Not designed for wide tongues
Made of a premium steel bar with an aluminum body, this hitch lock has an adjustable position and offers universal coupler compatibility. Thus, this trailer lock is a good one for you to purchase.

3. Shoreline Marine Trailer Coupler Lock

Shoreline Marine and Engineering has been in the business of marine products and accessories for a long time now, so I am confident in recommending this lock. While it is from a dependable company, I love how cheap it is. It is far from being the best, but at its price, it is a decent option.

This trailer coupler lock is a screw-type lock. Like a traditional screw, it has threaded patterns that will make it difficult to pull the lock smoothly without using the key. The only way to open the lock is to use the two keys provided.

The stainless steel construction of the coupler lock is another notable feature. It is a sturdy material, which is quite surprising given how affordable it is. From the weight of the lock, I can tell that it is built to last. It is also corrosion-resistant, so I don’t have to worry about potential damages in harsh environments.

Aside from being made of steel, the exposed parts of the lock are also brass-plated. This provides additional protection from wear while also increasing thickness. It can still be broken by a hammer or angle grinder, but before such happens, whoever plans to steal the trailer would have already been noticed.

If there is one drawback in this lock, it would be the jamming of the key. There are times when I have a hard time pulling the key out of the lock and I had to wiggle it to release it.
  • A good choice for budget-conscious buyers
  • Made of corrosion-resistant steel
  • Screw-type locking mechanism for a secure fit
  • Tough exposed parts with brass plating
  • Key is prone to jamming
This boat trailer lock is made of sturdy, corrosion-resistant steel and is a great pick if you are on a budget.

4. Master Lock 377KA Trailer Hitch Lock

Master Lock boat trailer locks are amongst the best in the world, and this specific product is one of my favorites. It is quite expensive, but it is worth every dollar. Compared to most of its competitors, it has a unique design, which initially captivated my attention. The sleek and modern look gives it an edge over many of its competitors.

The zinc construction of the lock is another remarkable feature. The protective shield prevents rust and corrosion. It will not suffer from premature wear, even with exposure to harsh environmental elements. From the way it looks, the solid coating does not seem to wear off easily.

I also like the versatility of this boat trailer lock. It fits 48mm, 51mm, and 59mm, which are the three most common sizes of trailer couplers. Whether the coupler is from Reese, Atwood, Valley, Fulton, or Dutton-Lainson, this lock works.

Best of all, the lock is backed by the manufacturer throughout its functional life. With the lifetime warranty, I am guaranteed its exceptional functionality through the years. If there is any issue, the brand will repair or replace the lock as needed.

The biggest problem is that all of the keys have the same patterns. This means that if there is another person with the same lock, he or she can use it to steal your trailer. It would have been better if the keys are unique.
  • Sleek and modern design
  • Zinc construction protects against premature wear
  • Fits most coupler diameters and brands
  • The manufacturer offers a lifetime warranty
  • Keys have similar patterns
Made by a prominent brand, this boat trailer lock has a sleek design, weather-resistant body, and universal compatibility.

5. Tow Ready 63228 Gorilla Guard Coupler Lock

Different from the traditional design of boat trailer tongue locks, this product offers maximum security. The lock is sitting in the front of the hitch next to a clamp above. It has a cylinder sliding lock that comes with tubular keys. While you need the keys for unlocking, to lock, all you need to do is push.

It is made of cast aluminum, which is known for being lightweight. Many of my favorite locks are made of steel, but that does not mean that aluminum is inferior. The reinforced aluminum guarantees many years of functionality. This material is hard to hammer, making it difficult to break. It looks like there is no weak spot that is easy to pry.

Every purchase comes with two keys. After receiving the keys, I suggest that you take a picture of them, especially the part number. In case you lose the key, contact Tow Ready and you can buy a replacement. The design leaves very little room for a bolt or cutter to get through, so you will need a spare key to unlock it.

The biggest drawback of this product is its price. If you are on a budget, I suggest looking for cheaper alternatives. Nonetheless, I believe that it is worth your money given its incredible features and benefits. Another note for you is that it is only for two-inch couplers, unlike others with universal compatibility.
  • A unique design ensures superior security
  • A simple push-button locking mechanism
  • Made of high-quality cast aluminum
  • Has two keys with unique code for easy replacement
  • Not for people on a budget
  • Only for two-inch couplers
With a cylinder lock that offers exceptional security and a cast aluminum body that ensures longevity, this is a great option for boat trailer security.

6. Master Lock 37KA-3 Trailer Padlocks

The price may initially seem discouraging, but that isn’t the case since it comes as a set of three identical locks. One thing I like is its key-retaining feature. This means that the key stays in place when it isn’t locked. This feature is a good way to prevent me from losing the keys.

If you are looking for uncuttable trailer locks, this is a good candidate. It has a 19mm armored shackle guard. Made of case-hardened steel, you cannot cut or saw this material, making it difficult for thieves to run away with your trailer. Even with a hacksaw or bolt cutter, it is almost impossible to take down this lock.

Speaking of its construction, it has a 4-pin cylinder and is non-rekeyable. This prevents picking, keeping your trailer safe. Plus, there is a dual-locking lever, making sure that the locking mechanism stays put unless it is keyed.

Meanwhile, the body is made of 40mm shrouded steel. It is thick and heavy, ensuring unrivaled durability. It is also weather-resistant, making it ideal even for outdoor applications. Just make sure to keep the key slot down to avoid the penetration of water in the interior.

Nonetheless, one problem with the lock is that many may find it to be too small. If you have a large hitch, this lock may not fit. If you use it in small hitches, meanwhile, there are a lot of wiggles. This extra space affects the tracking and movement of the trailer. It would have been better if there is a snug fit.

  • Comes as a set of three locks
  • Retains the keys unless they are locked
  • Tough steel shackle ensures solid construction
  • Can be used for outdoor application
  • Too small for most trailer hitches
  • Leaves a lot of room to wiggle
While it is small, this trailer lock is notable because of its sturdy steel construction and tough shackle that thieves cannot cut or saw.

7. Trimax UMAX100 Trailer Lock

From the first time I saw this lock, I knew it was going to be incredible. It has a solid steel body and ballistic-grade nylon housing, which tolerates even hammer blows. The crossbar and ball are also made of hardened steel. The combination of these materials ensures weather protection to prevent premature wear. It weighs six pounds. This trailer lock is a bit heavy, but it is also indicative of how durable the construction is.

The 9/16-inch shackle is also notable. It is thick and solid, which means that breaking it is almost impossible. I did not try to break it to test its strength intentionally, but judging from how it looks, I am confident that it will withstand the test of time.

I also love the covered keyhole in the nylon housing. This cover protects against dirt and dust, which can eventually make it more difficult to unlock. Meanwhile, the keyhole accommodates a seven-pin key, which has high-security features to minimize potential intrusion. Even if someone attempts to drill the lock, success is unlikely.

However, one issue with this lock is that it does not lock automatically. Instead, I need to turn its key. Also, the key does not have a snug fit, making it difficult to pull out. I often wiggle it a lot, and I am afraid that it will eventually break, even if the construction seems quite solid.
  • Durable steel body with ballistic-grade nylon housing
  • Has a thick shackle that is difficult to break
  • Seven-pin key minimizes the possibility of intrusion
  • Covered keyhole to keep dirt out
  • Need to turn the key to lock
  • The key is difficult to pull
With its steel body, thick shackle, and covered keyhole, this boat trailer lock has an exceptional construction and is worth giving a try.

8. AMPLOCK 5 Boat Trailer Lock

When it comes to boat anti-theft devices, AMPLOCK is one company you need to know. Based in Canada, the manufacturer has built a solid reputation for its diverse selection of the most reliable trailer locks. They are expensive, but the cost is justifiable.

Ducted cast-iron and heat-treated stainless steel are two of the main materials used in this lock. These are solid materials, making this lock one of the strongest of the products on this list. At about five pounds, it is thick and heavy. This makes it almost impenetrable, which also contributes to its incredible strength.

It is also worth mentioning that this lock is constructed to withstand different environments. Whether it is the sun or rain, it resists external factors that can damage the lock. It has good rust and corrosion resistance. I love how it has a shock-absorbing material as well. Upon heavy impact, the lock folds or bends, but it does not break.

Another good feature is the top-notch cylinder keyhole. It has a rotative face that isn’t easy to drill. Moreover, this trailer lock makes sure that they use tons of key combinations to prevent them from being alike.

To show their confidence in the quality and performance of the lock, the manufacturer is offering a five-year warranty coverage. Within such a period, it is guaranteed to be free of problems in workmanship!

The size of this trailer lock is one of its drawbacks. It fits only on specific two-inch couplers, so you should check out the complete technical specifications to avoid wasting your money. The lock is molded to keep a snug fit, which also makes it more difficult for thieves to break.
  • Made of durable cast-iron and stainless steel
  • Built to withstand different environments
  • User-friendly push and lock system
  • Covered by a five-year warranty
  • Fits only small hitches
Despite being expensive, this is an impressive boat trailer lock because of its solid construction, user-friendly design, and good warranty coverage.

9. Master Lock 379ATPY Universal Trailer Hitch Lock

With its universal compatibility, I can use it in any trailer hitch. It works on 48mm, 51mm, and 59mm couplers. As long as the trailer side has a ball, this lock works. Regardless of the size of the hitch, the installation is effortless. I don’t have to use any tool to secure the lock.

A trailer is often left exposed to the sun and rain, among other harsh elements. Hence, it must withstand damaging factors, including rust and corrosion. Furthermore, this model has a sturdy zinc body, which ensures long-term functionality.

For people like me who always lose things, this is also a good investment because it is rekeyable. This means that the old cylinder and pins can be changed to accommodate a key. Not to mention, it is keyed-alike, so I enjoy convenience.

I also like its ease of installation. Insert the key and position the ball of the lock on the unlatched coupler. Push the shield to the ball with enough force, leaving little room to move. Once it is secured, turn and remove the key.

As expected from Master Lock, it comes with a limited lifetime warranty. This warranty is similar to the other locks from the manufacturer I reviewed in this guide.

If you live in a place where it is always moist, the possible problem is that the moisture gets into the keyhole so it won’t be easy to open. If that happens, I recommend using penetrating oil to lubricate the mechanism or just apply more force.
  • Excellent rust and corrosion resistance
  • Convenient keyed-alike design
  • Easy to install on a hitch
  • Ensures long-term functionality
  • Moisture easily penetrates the keyhole
To conclude, this Master Lock universal trailer coupler lock has an impressive zinc construction and limited lifetime warranty.

10. Proven Industries 2516 Coupler Lock

This Proven Industries coupler lock defeated thieves! With its ¼-inch all-steel body, it is heavy and tough, preventing easy takedown. This lock is difficult to cut even with a bolt cutter. Plus, it has a black powder finish, which safeguards against environmental damages.

Another thing that I love about this lock is the three-piece design to ensure its security. There is a puck lock, inner shield, and outer slide. The shield and the slide are CNC laser-cut and tig-welded, making sure of a great fit. Plus, the lock is not keyed-alike, minimizing the chances of theft.

Having three components is also the reason for the lock’s versatility. Aside from securing my coupler, I can also use it on safety chains. It has an inner slide that works on both low and high-rated safety chains. The alignment tabs, meanwhile, will fit on the lock’s outer shield. Both the shield and the slide have a lifetime warranty.

In some trailers, the fit is quite loose, which means that there will be a lot of wiggle. I would have liked this lock more if it was tighter on the hitch. Also, the price of this Proven Industries trailer lock can discourage many people. Nonetheless, judging from its quality and performance, the cost should not be an issue.
  • All-steel body with a powder-coated finish for longevity
  • Three-piece system for exceptional security
  • Works on both couplers and safety chains
  • Lifetime warranty on shield and slide
  • Wiggles a lot once assembled
  • One of the most expensive on our list
From its all-steel construction to its three-piece locking mechanism, this boat trailer lock promises exceptional security and a visual deterrent against thieves.

11. Master Lock 1471DAT Coupler Latch Lock

This lock is from a reputable company, so I am sure that the quality is exceptional. Despite such, it is one of the most affordable on this list. Even if I am on a budget, I am confident that it does what it promises.

The design of this boat trailer locking pin is different from the other products in this buying guide. Whether the trailer is connected to a tow vehicle or unattached, the lock works. It has a 3.5-inch pin that prevents the removal of the coupler from the ball. When the lock is on, the hitch ball cannot be also positioned in the coupler.

While it is affordable, that does not mean that it has inferior construction. It has chrome plating to improve wear resistance. There is also a Weather Tough seal, which protects against environmental damage. Plus, it has a water-tight cap to prevent water penetration and keep the lock in its peak functionality.

Another good feature is the 4-pin tumbler design. This locking mechanism is more difficult to pick, minimizing the chances that your trailer will be stolen. The lock cylinder has a unique pattern that will make it almost impossible to open without the required key.

There are times when the keyhole isn’t smooth. Thus, it is difficult for me to pull the key out. Wiggling the key often does the job, but I am afraid of breaking the key while it is inside.
  • Budget-friendly lock with exceptional quality
  • Works regardless whether the trailer is connected to the vehicle or not
  • 4-pin tumbler design prevents picking
  • Key can be difficult to remove
One of the most affordable trailer locks, it has a chrome-plated body and water-tight cap, which protects against premature wear.

12. Trimax TCL65 Wheel Chock Lock

This lock is different from most of the products on this list because it is a boat trailer wheel lock. It locks the wheel instead of locking the trailer hitch. When locked, the wheel cannot rotate, and hence, the trailer cannot be towed.

Ease of installation is one of the best things about this lock. All that I need is to lock and chock it. Plus, it has universal compatibility. The bar quickly adjusts depending on the size of the tire. From trailers to ATVs, I can use it in different applications while being assured of the same great quality.

Made of heavy-gauge steel, I am sure that it lasts a long time. It is also rust and corrosion-resistant, so I have no problem leaving it outdoors. Even if it gets wet when it rains or with constant sun exposure, it is not quickly damaged. The powder coating provides an exceptional shield from potential problems.

Another reason why it has an impressive construction is the rubber coating in its arms. It creates a buffer between the metal part of the lock and the rims. This buffer prevents wheel damage by minimizing friction.

The other best thing is that the wheel chock has a lifetime warranty. This shows how confident the manufacturer is of its quality.

There have been many times when I had a hard time unlocking. I had to tap it repeatedly and wiggle the key just so that the lock would release. Also, dirt can quickly penetrate the keyhole, which is perhaps one reason why unlocking it is tricky.
  • Effortless installation on all tires
  • Heavy-gauge steel ensures durability
  • Rubber-coated arms to prevent wheel damage
  • Offers a lifetime warranty
  • Difficult to unlock
  • Dirt easily gets into the keyhole
Wrapping up, this trailer wheel lock is notable for its universal compatibility, powder-coated steel construction, and limited lifetime warranty. Hence, I highly recommend this trailer wheel lock.

What is a Boat Trailer Lock and How Does It Work


A boat trailer lock is a handy security device that prevents your trailer from being stolen. As the name implies, it locks the trailer to not be attached to a towing vehicle, making it impossible to move. It also acts as a visual deterrent, minimizing the possibility of trailer theft.

The main function is to attach the hitch to the receiver until the lock is opened. This way, no one can lift the receiver and move the trailer. They are available in different designs and vary in terms of how they attach to the hitch.

Types of Boat Trailer Locks

When buying a boat trailer lock, one of the most important things is to know the different types available. This affects their design and reliability, among other things.

  • Coupler Lock: This is the most common type and includes most of the products I reviewed above. It sits on the top of the trailer tongue. It has a ball that secures the coupler so that it cannot be connected to a tow vehicle.
  • Pin Lock: A locking hitch pin slides into a hole where the frame meets the hitch. When the lock is on, a towing vehicle will not connect to the trailer, which is what makes it impossible to steal.
  • Wheel Lock: Instead of locking the coupler or hitch, it locks the wheel. It has an adjustable bar to fit wheels of different sizes. When the wheel is locked, it will not rotate.

Benefits and Drawbacks of Using a Boat Trailer Lock


The best thing about using a trailer lock is that it prevents trailer theft. It is your first line of defense against robbers. It is easy to notice, making it a great visual deterrent. When someone sees that the trailer is locked, they will think twice about stealing it. This will minimize the chances that you will be victimized by ruthless burglars.

If there is one drawback, it would be the cost, especially if you will buy those from high-end brands, including Proven Locks. Honestly, I do not find any con because it is a worthy investment, especially in terms of peace of mind that it gives to trailer owners.

Buyer’s Guide

To differentiate the options, below are the most important considerations.


The material of the trailer lock impacts its overall quality, especially its durability. Stainless steel is one of the most popular. There are also lighter alternatives, which are made of aluminum. Pick a strong material so that it is difficult to break. Otherwise, it can be easily cut using a saw or crowbar, among other tools.

It is also good if the lock has a powder coating. It reinforces the main material, protecting against rust and corrosion. This powder coating is also a shield against environmental factors that can speed up damage, making sure that the lock withstands outdoor use.


Pay attention to the technical specifications of the lock and look if it is suitable for your trailer. In a trailer hitch lock, make sure that it fits the coupler. There are three main sizes of couplers – 48, 51, and 59mm. Consider buying an adjustable lock that accommodates all these sizes. Meanwhile, if it is a wheel lock, make sure it fits the width of the trailer.


A top-notch boat trailer lock does not only secure the hitch or wheel. Instead, it also acts as a visual deterrent. Make sure that it is easily visible, such as by choosing a bright color. When thieves see this, they will most likely be discouraged.

Ease of Use

Some trailer locks are complicated to use. Pick one with a user-friendly design, which means that locking and unlocking should be a breeze. The key must slide smoothly and pull without a problem. Hooking it on the hitch, receiver, or wheel should be effortless.

Locking Mechanism

This factor is indicative of how strong the lock is. The pin or the barrel should be strong enough so that it can resist picking. You will also benefit from having a lock with a unique key, which minimizes the chances of being unlocked by others.


If the manufacturer is confident of the quality of their boat trailer lock, they will not hesitate to offer a long warranty. The minimum is one year, but the best ones are those with a lifetime warranty. The manufacturer must warrant the lock to be free of problems in workmanship. Otherwise, they should offer free repair or replacement.

Care and Maintenance

Keep your lock in its peak performance over the years. Here’s how you can take care of it:

  • Regular lubrication is a must, especially if you live in a cold environment. Use dry lubricants. After spraying, push and pull the key to lubricate the locking mechanism, making it smoother.
  • Use a can sprayer with compressed air. This will blast dirt off the keyhole. It removes stuck dust or debris.
  • Position the trailer properly, especially for long-term storage. Keep in a place with shade or where it won’t easily attract dirt to maintain the lock’s good condition.

Frequently Asked Questions


Who makes the best boat trailer lock?

Master Lock, Reese Towpower, Shoreline Marine, Trimax, and Proven Industries are some of the top brands worth considering when searching for a boat trailer lock. They have years of experience in making high-quality locks, so I am sure that their products are second to none.

How do you keep a boat trailer from being stolen?

The best way to keep a boat trailer from being stolen is to use a lock. However, this isn’t enough deterrent, especially amongst thieves with sophisticated tools. It also helps to keep the trailer in a secure location and a place easily visible. Put it somewhere with high foot traffic. Installing a security system also helps.

If possible, cover the trailer when it is parked, especially when there is a boat. This will keep the boat out of the prying eyes of thieves. The more visible a boat is, the more attractive it will be to robbers.

How to set-up and use?

Knowing how to lock up a boat trailer is crucial to making the most of the lock. Setting it up will vary depending on the lock you will use. Connect the hitch to the receiver and position the lock on the top. Push the lock bar to secure its position. In some cases, you will need to turn the key to lock the bar. Pull to be sure that you have locked it properly.

What should I do if I lose my keys?

The best thing that you can do is to call the manufacturer and ask for a spare in case you have noted the record number of the broken key. Alternatively, you can also have the key re-keyed, if its construction permits the latter. If all else fails, resort to sawing or grinding, among other methods to unlock the trailer.

Where can I buy?

I suggest buying a boat trailer lock online. Check out Amazon, Walmart, and Home Depot, among others. They have a diverse selection of locks from different brands. Many users are generous enough to share their real-life experiences through reviews, making it easier to compare the alternatives. By the way, you also can refer more other types of boat accessories such as boat trailer jack, boat trailer winch, and etc if you want.


Don’t be the next victim of trailer theft! The best boat trailer lock promises reliable protection. It connects the hitch to the receiver or locks the wheel, making it impossible to unlock without a key. From coupler to pins, these locks exist in all shapes and sizes. It is crucial to pick one that matches your trailer. Just take note of my recommendations above and it is hard to go wrong!

5/5 - (5 votes)