The Cooler Master SK621, SK631 and SK651 are wireless versions of the few months older flat keyboard series SK630 / SK650.
Cooler Master SK621 vs SK631 vs SK651
The second digit in the keyboard’s name correlates with the size of the keyboard. The SK651 is a full size keyboard, the SK631 is a tenkeyless keyboard (without numpad) and the SK621 is even smaller than that, it features a so called 60-percent size. The keyboards basically only differ in size, their set of features is the same for all three models.
Mechanical Keyboard with Bluetooth
Buying the SK621, SK631 or SK651, you will get a mechanical keyboard with support for Bluetooth 4.0. The integrated battery promises up to 15 hours of wireless operation with illuminated keys. When illumination is disabled, one charge of the battery is supposed to last for several months. To charge the battery, you simply plug in the USB-C cable, the keyboard then automatically changes into wired operation mode.
As for the rest, the SK621, SK631 and SK651 are equal to the SK630 / SK650. The keyboards feature Cherry MX Low Profile Red switches, RGB lighting, n-key rollover and they offer various configuration options, even without software.
Tech Specs for Cooler Master SK621
Further Information on Amazon.com
Mechanical Keyboard Score
The mechanical keyboard score is our overall score for a keyboard. The score is based on the available ratings and critics and makes an easy comparison between different mechanical keyboards possible. It is also used for our mechanical keyboard ranking.
August 13, 2019
"The compact nature does give off a bit of sticker shock initially, but once you see and use the feature set, and get used to the layout of the keys, the SK621 overshadows any doubts in cost. While not a device everyone will gravitate towards, those who do will be rewarded for their choice!"
June 4, 2019
"The Cooler Master SK621 keyboard is a solid keyboard with great typing feel, but it takes time to get acclimated to the modified key layout."
May 9, 2019
"The Cooler Master SK621 performs really well, and doesn’t feel cramped even considering its incredibly small size. It’s not cheap, but if you’re looking to de-clutter your desk and go for a more minimalist setup, the SK621 is definitely one to look at."
May 9, 2019
"Even so, £140 is too high a price for me to recommend this keyboard (not least because it’s $120 in the US), despite the fact I can definitely see its appeal, and I’d certainly not stop anyone buying it if it fills their particular niche."
May 7, 2019
"The first thing is that you are going to need to get used to the 60% layout. ... The next thing you are going to have to get used to is the design of this keyboard. ... That aside typing on the SK621 is a very enjoyable experience."
May 7, 2019
"Cooler Master’s smallest (60%) wireless/wired mechanical keyboard strikes a contentious balance between form and function. But if you like flat caps and are willing to live with a few oddly placed keys for the benefit of extreme portability, it should serve you well."