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Master Lock 5900D Review

Many houses have a special safe installed that allows you to keep your most valuable possessions safe from anyone who would want to take them from you. These safes are almost always big and impossible to carry around, so sometimes you may want something smaller to keep your handheld valuables safe.

That’s where products such as the Master Lock 5900D come in, as they can help to keep some of your smaller, valuable items safe from harm no matter where you may be. In this review, we will take a look at this little safe and show you what it can and can’t do.

This way, you will have all the information you need to decide whether it’s worth adding to your travel tools. Let’s begin and unlock the secrets of this safe product to see what it’s all about!

Key Takeaways

  • A Master Lock lockbox is perfect for travel and other circumstances, as it allows you to keep your smallest valuables safe from harm.
  • Master Lock is an established company that has been operating for over 100 years.
  • The lock box is small enough to carry with you on vacation or any travels.
  • You can set your own 4-digit code in order to make it even easier to operate.
  • The lock box is water resistant with special ports for charging or headphone cables.

Overview of Master Lock 5900D

The concept behind the Master Lock 5900D is simple: it is essentially a small safe you can carry around with you. If you’re traveling (or leaving the house for any reason), it can be difficult to keep things like your keys, passport, or electronics safe from harm.

The 5900D allows you to group your small valuables together in a casing that is secure, durable, and water-resistant. There is a bit more to it than that, and we will cover all of the features and benefits this lock box has as we proceed through the review.

For a quick look at the Master Lock 5900D in action, you can check out this short and informative promotional video.

Why You Should Consider a Master Lock Portable Small Lock Box

Combination safes, locks, and other secure devices have become rather popular in recent years. We have previously looked at products such as the Eufy video smart lock that is perfect for home security. That product is great for the door of your home, but what about when you leave your house?

There are a few items we all tend to carry, items that we want to keep safe. These include things like smartphones, wallets, and other electronics; it can be nerve-wracking to try to keep them all safe from theft and harm.

This is especially true when traveling long distances via plane, as the likelihood of theft and damage increases exponentially. The Master Lock portable lock box offers a great solution to this problem.

This product not only allows you to keep your valuables in one convenient location but also keeps them safe from damage, loss, or tampering. The box is especially handy for travel but could also be great for everyday use.

If you need a larger safe for bigger items or more permanent fixtures, be sure to look at this list of some of the best safe products we have seen.

Master Lock 5900D Review

About the Master Lock Brand

When considering whether to purchase products from a company, it’s always reassuring to know that the company is well-established and has been around for a long time. This is certainly the case with Master Lock, as they have been around for over 100 years. It has allowed them a lot of time to master (no pun intended) their product range, and this longevity shows why they have endured for so long.

Key Features and Benefits

  • Small Size- The lock box is small enough to be highly portable, making it ideal for travel or work usage.
  • Cable Attached- Attached to the lock box is a durable cable. It can be used to secure the box to something temporarily or as a carrying strap.
  • Customizable Code- The 4-digit code to unlock the box can be easily customized. This ensures that you can use a code that you will never forget.
  • Access Port- There is a convenient cable port so that you can charge devices or listen to music even when the lockbox is closed.


The design of the 5900D is simple and efficient. As mentioned, the box is small and portable, and it has dimensions of 5.1″D x 9.41″W x 2.2″H. It has a pill-shaped design with a sleek black and grey color scheme, which means that it won’t draw too much attention.

Small and Compact

Sometimes, you may want a larger safe to keep your possessions safe. However, the 5900D is designed for travel and convenience, so its small size makes it perfect for these purposes. The dimensions are small enough that you can fit it easily in a backpack, carry-on, or perhaps even a large pocket.

Performance and Reliability

The 5900D lock box is pretty simple, but this simplicity leaves a much smaller margin for error. It is durable and portable with great features. Everything works well thanks to the sturdy construction.

You can rely on the lock box to keep your valuables safe from most harm, and you can ensure it is always by your side thanks to its portability.

Set Your own 4-Digit Code

There are so many passwords and codes we need to learn in our everyday lives, so it’s always great when we can set them ourselves. This is the case with the 5900D, as you can set your own personal 4-digit code to have a code you will easily remember.

Customer Service and Support

Even when a product is of high quality and can be relied upon, you may find yourself running into issues. If you do, then it is easy to contact Master Lock for assistance, or you can try to solve the problem yourself using their comprehensive support page.

If you need more specialized support, you will find options to contact them via phone or with a support ticket on their contact page.

Pros and Cons


  • Small and portable.
  • Durable.
  • Customizable code.
  • Water-resistant.
  • Access port.


  • May be too small for some devices or objects you may want to carry with you.

Water Resistant, Ear Bud/Charging Cable Access Port

Water damage can be catastrophic to electronic devices and certain documents, so the 5900D is water resistant to protect anything inside from potential water damage. Additionally, there is a convenient access port built into the case.

This will allow you to store something like a smartphone inside it while still having the ability to charge it or have headphones plugged in.

A Brief Look at the Competition

We have previously looked at other small lock devices. For example, we have looked at the Kwikset SmartCode 914. This kind of device has more comprehensive unlocking options and customizable codes, but it lacks the portability of the 5900D.

You also have options such as the Amazon Basics Portable Security case which is more comparable to the 5900D. While it has its benefits, it’s a bit less versatile with what you can store, and the 3-digit code makes it slightly less secure.

Last updated on May 28, 2024 4:14 am


The big question at the end of this review is “Is the 5900D worth getting?” The quick answer to this question would definitely be a yes as far as we are concerned. While it’s not the fanciest, feature-rich accessory ever made, it does what it sets out to do admirably, and it will certainly help to keep your small valuables safer no matter where you may be.

Conclusion and Where to Buy

We hope that this review has given you a better idea of what the 5900D has to offer and that it will help you to decide whether it’s right for you. We would recommend this to anyone who may be traveling a lot or who may need a safe for their valuables while on the job.

If you would like to purchase one for yourself, then you can find it on this Amazon product page for around $33.

Frequently Asked Questions

How Many Items Can Fit in Master Lock 5900D?

This will depend on the items and their size, but it should be large enough for 2-3 smaller objects.

Can a Bolt Cutter Cut a Master Lock?

Most bolt cutters would be ineffective against a Master Lock thanks to the design.

Can You Change the Combination on a Master Lock?

You can change the code on your Master Lock, as you can set your own 4-digit code.

Are Master Locks TSA Approved?

You should have no problems taking a Master Lock on most airlines.

Can You Open a Master Lock Without a Combination?

You will need to have the correct code in order to open the lock conventionally.