Cooler Master SK621 Mechanical Keyboard Review

If you are among those who tend to travel a lot and would love to have a keyboard that can stick with you, chances are you’re probably disappointed. There aren’t keyboards out there which are good and low profile. In CES 2019, Cooler Master addressed those disgruntled folks and released the SK621. But the SK621 is more than that. It has all of the fundamentals needed for a keyboard to make its mark- RGB, small form factor and mechanical keys. This is a great keyboard with not just immense portability but great build and performance too.

Cooler Master SK621

Best Low Profile Mechanical Keyboard


  • 14 hours battery time
  • Cherry mechanical keys
  • A strong and durable build
  • Low profile and light weight makes it easy to carry around


  • Long switch stem

151 Reviews

Material: Aluminum and Plastic | Response Time: 1ms | Switch Type: Cherry MX RGB Low Profile Switch | Polling Rate: 1000 Hz | Travel distance: 1 ms

VERDICT:A great low profile keyboard with top of the line mechanical keys. The SK621 skimps out on nothing and offers an incredibly satisfying, and silent experience with its Cherry mechanical keys and great battery life. This keyboard is the near perfect companion for the frequent travelers.

The SK621 is a 60% keyboard, meaning it cuts down on the extra bezels and keys that traditional keyboards offer. By doing so, it sports a much smaller form factor, making it very easy to carry around. Cooler Master has not skimped out on performance with this keyboard either as it has very responsive Cherry red mechanical keys. With a response time of just 1ms and a travel distance of 3.2mm, it makes typing and gaming very smooth. This wireless keyboard comes with a USB Type-C cable and a very generous battery time. Even with the RGB lights on, it can last for 14 hours without dropping down on performance. At the cost of a few multimedia buttons and a numeric pad, you get a great keyboard with the industry standard mechanical keys.

Cooler Master SK621 At First Glance

Simply put, we were very satisfied with Cooler Master’s newest addition to the wireless keyboard- the SK621. However, there were some quirks that got to us that we disliked. The keys employ the cherry mechanical switches which simply work great. However, this keyboard is intended to be used primarily as a portable device. Cooler Master makes use of the stock switches with the long stems. This gives the SK621 a rather long height which goes against its ease of portability. Additionally, you may need to invest a bit more in purchasing a separate Bluetooth dongle as SK621 does not have one.

Metal Base

Design and Build

This keyboard has been packaged in a cloth bag which gives it that extra bit of protection if you need to carry it around. And since the SK621 has been marketed as they keyboard for portability purposes, the extra bag sure does help. With only 65 keys on this keyboard, it’s width comes off to be similar to the keyboards used in laptops. It is made up of plastic and aluminum with 4 rubber feet at the bottom. It rocks a chrome ring around it which looks great when the RGB lights are turned on. The primary colors are black with just a tad bit of silverish shades on the outer rings and sides. Moreover, you’ll notice that there are almost no bezels. The SK621 itself is slightly tilted upwards however there is no clip to switch towards a more steeper angle.

The SK621 is a 60% keyboard however still has all the necessary things you’ll need out of a keyboard. However, with this smaller form factor comes a keyboard without a numeric pad. It is quite common to see keyboards of smaller form factors to remove the numeric pads so no surprise there. Once you see this keyboard up close, you’ll notice just how compact and small this is. However, you’ll notice that along with the omission of the numeric pad, there are no multimedia function keys either. Instead, there are function keys embedded in it which you can access by holding down the function button.

Cherry Red Mechanical Switches

As said earlier that although this keyboard has a much smaller frame size, it does not skimp out on anything. Mechanical keys are the way to go right now, preferred by everyone in the industry. The SK621 has all mechanical keys- or in this case, they’re Cherry red mechanical keys. Mechanical switches give a more tactile feel compared to normal rubber membrane switches. Pull off the keys and you’ll notice that every key has an LED underneath it. This really helps maximize the lighting effects on this keyboard that you can control with the software.

Cherry Red Switch

The Cherry mechanical switches are rated to withstand over 50 million presses. The best part is that they will register all those 50 million presses at once. Cherry red mechanical switches have an actuation force rated at 45g and they are simply great. The sound is very satisfying with these and you are sure to have a very enjoyable experience. The square-shaped keycaps are really well designed and have a floating look to them when viewed from the side. The keycaps have the ideal distance between them, making them easy to differentiate from other keys.

These keys have a travel time of 3.2 mm and an actuating distance of 1.2 mm. Additionally, cherry mechanical keys are linear switches which means that they require a full press of the button to actually register a key. Another thing that stood out to us was the fact that these keys have quite a large stem. Now that is an entirely personal preference and some might not even notice it at all. But it does go slightly in the opposite direction when the SK621 is intended to be a low profile keyboard.

Low Actuation Force

Cherry mechanical keys are intended for fast typing with instant response time and gaming intents. That means that you can use it as a go-to keyboard for conventions etc, as well as your backup alternative for gaming. Take the SK621 along with you and you’re guaranteed to get a very good performance out of it. The top plastic has a nice blend of gripping and slippery texture. One thing people should know is that the 60% slogan refers to the reduced size compared to normal keyboards. As it cuts down on the extra bezzles and keys, it also results in having smaller keys. For the most part, the small key size is not a problem however small enter and shift keys do cause some problems. Especially, if you’re used to normal bigger sized keys.


Hybrid Connectivity

This keyboard is a wireless and wired keyboard and comes in the box with a USB Type-C braided cable. Even though it has RGB lights, it still managed to last for a little less than 14 hours. That honestly, is pretty amazing and we were very surprised and relieved to see that. Given that this keyboard will primarily be used by travelers, this bonus battery is surely a step in the right direction. On the left top corner is a little switch that must be toggled to activate the wireless capabilities. And as for the wired connection, it takes USB Type-C cable to be connected to the computer. When has a Type-C cable ever gone wrong? In order to check out the remaining battery life, you press the Caps Lock key and it enables a colored LED.

The SK621 pairs up very quickly with devices with its Bluetooth 5. In some cases, we did experience the Bluetooth connectivity being sort of a hit and miss but that was really minor. The SK621 can pre-store up to 3 devices and connect with them instantly. There are hotkeys on the keyboard labeled 1,2 and 3 along with the Bluetooth icon. With the Bluetooth toggled on, you can press that and instantly connect to those pre-stored devices. This helps out a lot in ensuring quick connections. As for the connection itself, we witnessed no lags when switching to wireless. The response time was still fast and quick. The SK621 is Cooler Master’s first wireless keyboard and they did not fail any expectations.


By installing the latest version of the Cooler Master Portal, you can have access to the software side of this keyboard. It should be noted that the Cooler Master Portal itself is not a dedicated SK621 software app, rather it is a hub for more Cooler Master products. With this installed, it automatically detects the keyboard provided you have it connected with your PC via a wire or Bluetooth. It provides a lot of options for different settings and profiles. Along with having customized profiles, you can also set up macro keys for whatever purpose you seem fit.

Other than that, the software will also let you fully customize the LED profiles and choose which mode you want. After choosing a color mode, you can further modify that. With the colors and 256 brightness steps, you have 16.8 million colors on your hand to play and fiddle with. These modes include a different color per key, cool fade away effects, multi-zone colors and many more.


The SK621 by Cooler Master is a unique keyboard for a number of reasons. Despite being on the smaller and lighter scale of things, it performs really well. The cherry mechanical keys are instant, snappy and very responsive. Moreover, the Bluetooth connections are a walk in the park with them being fast and reliable even when a few meters away. The SK621 also has RGB lights under it which are fully customizable, and even with them turned on, this keyboard manages to stay turned on for 14 hours.

The new minimalistic masterpiece

The few minor quirks that it does have, are very easily ignorable. We highly recommend this keyboard to not just travelers but the desktop uses too looking for a minimalistic keyboard for more real estate on their desks.

Price at the time of review: $120


User Rating: 3.3 ( 3 votes)
Bill Wilson
Bill is a certified Microsoft Professional providing assistance to over 500 remotely connected employees and managing Windows 2008 to 2016 servers.