Cooler Master MasterKeys L PBT Review

By: Hai Wang
September 22, 2017

If you are a motorsports fan like me, you probably have wondered how cool it could be to drive a race car to on the street. I remember a YouTube video about Lancer Evolution rally car serving as a taxi. It is just so cool to see or hear a race car, despite the fact it may not be legal to drive on public road, haha. However, while driving a race car for fun is one thing, on a daily basis, it is totally different. First of all, there is no air conditioning and audio equipment due to weight reduction measures. Secondly, the race car is slow in traffic due to the low torque output at lower range RPMs. Thirdly, everything is so heavy to use on a race car, since the whole car is mechanically reinforced. For example, a twin plate clutch is implemented to deal with the high horsepower. The twin plate clutch requires double the force you need to apply to a single plate clutch. The extra energy you have to spend on driving itself is probably the most significant drawback of driving a race car for daily use. However, all of these sacrifices are essential if you want to win a race. When you get to the competition level, being mushy or soft is the last thing you want, because you know you are going to push the car to the limit. I guess for some people, being hardcore is more important than saving energy. The same for using a keyboard, if you are really into those keyboards that require higher actuation force than any other things in the market, then the Cherry MX Green switches will be a nice choice. Today's review unit, the Cooler Master MasterKeys L PBT keyboard, features the hardcore Cherry MX Green switches, and is also designed to deal with heavy and longtime use. Is it just a mechanical gaming keyboard for a hardcore gamer, or it can really balance both the gaming and productivity work? Let us read on and find out.

The Cooler Master MasterKeys L PBT arrived via FedEx to us here in Calgary, Alberta, Canada. As you can see from the picture, the parcel is clean and mostly intact. After thousands of miles of transportation, there is not only one dent on the corrugated cardboard. As always, I was not the person who received this parcel in the first place, since the package was delivered directly to our Editor-in-Chief Jonathan Kwan.

A good retail package design should be consistent with the design of the actual product. Considering this requirement, the retail container of the Cooler Master MasterKeys L PBT does the job fairly well. It looks the same as the MasterKeys S PBT. For a keyboard retail package, you will usually see a picture of the product in front. In my opinion, if the product picture is located in the middle of the front cover, then everything around should not be too different in style. For example, if the keyboard has a classic and low key design, it would be inappropriate to use a fashionable background or some abnormal fonts. In this case, the background color is matte black, which is consistent with the color of the product itself.

By looking at the picture, my first impression about this product is that it is designed by someone with access only to a ruler. You can hardly find any round lines from the picture of the keyboard. For those who like classic looks, this keyboard is for you. In the left section of the package front cover, the company’s logo, name, and the product’s name are printed in grey. The color chosen for the logo and names makes sense, since the focus is still in the middle section of the package front cover. In the bottom right section, several key features of the MasterKeys L PBT are listed. Those features include the use of Cherry MX Green switches, PBT keycaps, and US keyboard layout. Rather than intending to catch your eyes, the way Cooler Master presents those features is more likely to keep the whole picture balanced. Overall speaking, there is nothing wrong with the retail package design. Regarding the overall impression, I would say it is rather well balanced.

Before we move on, the specifications of the Cooler Master MasterKeys L PBT from its official website is listed below:

Product Name: MasterKeys L
Material: Plastic / Metal
Color: Black
Polling Rate: 1000 Hz
Repeat Rate: 1x / 2x / 4x / 8x
Response Rate: 1ms
MCU: 32bit ARM Cortex M0
On board Memory: 512KB
On-the-fly system: Macro, Repeat Rate, Win Lk
Cable: Detachable with Micro-USB
Connector Cable: USB 2.0 with Braided
Cable Length: 1.5 Meters
Product Dimensions: 440 * 137 * 28 mm
Product Weight (without cable): 1140 g
Warranty: 2 years

Peeling the retail packaging off, we can see the all black cardboard container of the keyboard, which includes the keyboard itself, an USB cable, seven red keycaps for gaming, keycap puller, and a user's manual. The keyboard is wrapped with a piece of white foam wrapper, which can provide protection to the plastic surface from scratches. The user manual serves as a quick reference of the functions. There are twenty-three combinations of functions including the keyboard layout switch, macro control, media player control, etc. Remember, the keyboard does not come with any additional software, therefore keeping a quick guide around you for the first little while is necessary. The user's manual is printed out using good quality paper, and it is easy to read.

As I have mentioned before, the Cooler Master MasterKeys L PBT was likely designed by people with access to only a ruler. From the above picture, we can clearly see the keyboard is composed of all straight lines. There are no round lines I can find on it. This is what the MasterKeys PBT series is all about; if you want something similar but smaller, look for the review from my colleague Aaron, the Cooler Master MasterKeys S PBT. With the matte black color, the keyboard has an obvious stealth look. For a well-balanced keyboard, there is nothing wrong with such a low-key and conventional design, since getting the job done is everything, and anything else is unnecessary, right? By the way, this keyboard does not have a palm rest. If there is a rule that says "a good keyboard should have a palm rest", then I believe Cooler Master definitely wants to break it, haha.

The dimensions for the MasterKeys L PBT are 440 mm in width, 28 mm in height, and 137 mm in depth. It is a compact keyboard with ten keys, thus it will not take too much space on your table. This keyboard weighs about 1.14 kg, which I think is a little bit heavy, but since this is a mechanical keyboard, this is no surprise. It is generally sturdily built and has very little flex, even if you really try to twist it hard. The keyboard makes a very slight creak if you try to hold it just on the edges. The rigidity is contributed by the hard plastic and, more importantly, the metal plate inside the chassis.

Thanks to the number pad, the MasterKeys L PBT features a standard 104-key instead of the MasterKeys S PBT’s 87-key QWERTY ANSI layout. It is worth noting the Enter key is single row, which is good news for people who like a full size right Shift key. Similar to the other keyboards from Cooler Master, there is no Windows logo on the Windows key. Instead, the Windows key has Cooler Master’s company logo on it. I guess to refer to the key as Windows key is not precise, since the key layout of this keyboard can be changed on the fly. Pressing Fn + Right Ctrl + W changes the layout to Windows, while pressing the same preceding keys with M or L changes the layout for use on Mac or Linux, respectively.

One of the selling points of the MasterKeys L PBT is the use of polybutylene terephthalate, or PBT, to make the keycaps. Comparing with the commonly used ABS, or acrylonitrile butadiene styrene, PBT is mechanically strong and is less likely to shine after long time use. It is worth noting that the MasterKeys L PBT is not a backlit keyboard. Since it is hard to find anything without LEDs, I will say the Cooler Master focused on providing a nice typing tool this time, rather than something showy and superficial. I do not think anyone will use a keyboard in a completely dark situation. Furthermore, typing enthusiasts are probably able to touch-type, which means you will not even need to look at the keys. Therefore, the lack of lighting is not a problem.

The MasterKeys L PBT strikes a very good balance between gaming and productivity use. There are two major functions that can boost the gaming experience. First, the macro key function is really a gaming performance booster if you want to try out new games. The macros can be recorded without using any software or driver on your computer, although you need to carefully read the instructions or you may not be able to find out how to record macros. Once the macros are recorded, users can also control how many times the macros are activated. By pressing the Fn + Print Screen, the macro will be activated once, while by pressing Fn + Scroll Lock, the macro will be repeated. Clicking the Fn + Pause will allow a macro to repeat infinite times. The second gaming performance booster is the Windows key disable function. I like this function a lot, since I used to accidentally press the Windows key when trying to use the left Control key. These two gaming performance enhancements can definitely win you some advantages in battle.

Speaking of non-gaming usage, the MasterKeys L PBT is capable of delivering a high-quality typing experience. However, in terms of boosting up the productivity, this product is not perfect. There are no Fn-modifier secondary function keys related with productivity work. Functions such as quick email access, calculator access, and web browser access are missing. As a student in engineering, I would really appreciate a calculator quick access function. This keyboard allows you to control your media player using Fn + the six keys above the arrow keys. There is no need to look up the user manual for media player related functions, since all of those secondary functions are indicated by the small icons on the keycaps, as shown in the above photo. Those small icons are self-explanatory.

As a mechanical keyboard, the MasterKeys L PBT features Made in Germany Cherry MX Green switches. The mechanical key switches are the most important parts on the keyboard, since they define the quality of tactile response and typing experience. If you are not familiar with mechanical keyboards and switches, there are three major types of keyboards we can buy today. Type one is the membrane keyboard, which features low manufacturing cost, but a rather poor typing experience. Mostly because of the low cost, low noise level, and possibility of using it in low profile applications, the membrane keyboard is the most common one on the market. Type two is the improved version of membrane keyboard. The improvement lies in the use of a scissor-like structure, which can improve the typing experience in the switch. This type of switch is mostly used for laptops. Type three features mechanical switches that provide the best tactile response and typing experience, and they are referred to as mechanical keyboards. The Cherry MX Green switches are pretty hardcore to say the least. Not only are they clicky, but they also require a high actuation force. In fact, I missed few letters when I tried to type on it for the first time, since I was not prepared for the high resistance. However, after getting used to it, the typing experience is really awesome. As for the clicky sound, as long as your other coworkers or roommates do not mind, then it is okay. By the way, the lifecycle of the Cherry MX Green switch is rated at 50 million keystrokes. Combining with the PBT keycaps, this product is meant to be used for a long time!

The MasterKeys L PBT is a full NKRO keyboard. NKRO stands for n-key rollover, which means there will be a maximum n keys being registered simultaneously by the keyboard. If the number of keystrokes at one time, say m keys, exceeds the number of n, those (m - n) keystrokes will not be recorded by the system, and ghosting may happen, such that some of your actions in the game will be ignored. I remember when I played Need for Speed Underground 2 on my laptop a few years ago, I could not use my nitrous while turning. This is because the laptop only supports two key rollover. The NOS, turning, and acceleration required three keys to be registered simultaneously.

The MasterKeys L PBT is a wired keyboard and therefore, requires a USB cable to connect to the computer. The USB connection of this product is realized by a 1.5 m long braided cable. As you can see from the above photo, the cable is detachable through the micro USB connector. I personally prefer to not have detachable USB cable on my keyboard, since the more connectors you have, the higher chance you will get bad connections. In this case, my suggestion is to avoid frequent plugging and unplugging of the micro USB connector, since you do not want to wear it out. The USB connector of the MasterKeys L PBT is gold plated. Note that gold plated connectors are only there to make the keyboard look good. There is no actual performance improvement regarding data transmission. At the bottom of the keyboard, there are four pieces of rubber strips: Two at the back and two at the front. All of those rubber feet can provide enough grip to allow the keyboard to be as stable as a rock. Two risers at the front feature adjustable rising levels. It is worth noting the risers are also rubberized to enhance the stability of the keyboard when risers are used.


After a few days of using the MasterKeys L PBT with legit Cherry MX Green switches, I find it hard to give the keyboard a fair evaluation just by the ostensible impression it gives me. Starting with the looks, this product features an incredibly simple and conservative design. It is almost impossible to find a unique feature just by looking at it -- and for a lot of people, this is a good thing. In terms of typing experience, the Cherry MX Green switches require me to take a while to get used to the high resistance. For the lack of backlighting, I can hardly find anything wrong with it, since it is just irrelevant with typing. However, there will be others who find this missing feature a bit disappointing. The MasterKeys L PBT is not just another nice-to-have keyboard though. The amazing features about this product are mostly hidden inside. This is specifically found in the German made Cherry MX switches. You might not show it off at a LAN party, but it definitely feels crisp and clean. To further enhance the durability of the keyboard, PBT keycaps are used to deal with heavy use over a long period of time. After years, when you bring your MasterKeys L PBT to the LAN party again and all your friends’ fancy keyboards are shining like mirrors while yours are still matte black, then you will know you have made the right choice. The MSRP of this keyboard is $90 USD. I believe the MasterKeys L PBT is definitely worth this price, since you can surely enjoy it for a long time -- and this may be what matters most in the end.

Cooler Master provided this product to APH Networks for the purpose of evaluation.

APH Review Focus Summary:
8/10 means Definitely a very good product with drawbacks that are not likely going to matter to the end user.
7/10 means Great product with many advantages and certain insignificant drawbacks; but should be considered before purchasing.
-- Final APH Numeric Rating is 7.7/10
Please note that the APH Numeric Rating system is based off our proprietary guidelines in the Review Focus, and should not be compared to other sites.

The MasterKeys L PBT is not a keyboard you will show off at a LAN party when it comes to bling, but it is a durable product with the hardcore typing experience you can enjoy for long time.

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