Cooler Master SK621 review: a compact keyboard for creative pros

This customizable mechanical keyboard is a worthwhile travel companion if you're OK with trading some productivity for portability.

With its luxe design, multi-colored backlighting effects, and customizable controls, the Cooler Master SK621 aims to give creative professionals the functionality they need without sacrificing the artistry they crave. It mostly delivers on this promise, but the compact mechanical keyboard’s 60-percent layout can be a hurdle if you’re unwilling to give up some typing comfort and accuracy for the travel-friendly size.


Measuring 11.5 x 4 x 1.1 inches and weighing about a pound, the SK621 is small and light enough to carry comfortably in a laptop bag or backpack. Of course, there’s a trade-off for that portability. In order to achieve the compact 60-percent layout, designers had to eliminate a number pad and other landmarks of a full-size keyboard. Many of the dedicated functions such as Home and Page Up/Down, as well as multimedia playback controls, have been added to alphanumeric keys. Others have been reduced in size and relocated to new positions on the keyboard.

Cooler Master has devoted a lot of attention to aesthetics. The keyboard features a brushed aluminum top plate, floating keycaps, RGB backlighting, and gold trim around the chassis. The attention to detail extends to the accessories, as well: a braided USB Type-C cable for battery charging and wired connectivity, and a velvet tote sleeve. Despite this emphasis on eye appeal, the SK621 feels sturdy and built to last.

sk621 01 us Cooler Master

The SK621 blends aesthetic appeal with durable build quality.

The SK621 uses Cherry MX Low Profile switches to provide the reduced actuation point (1.2mm) and key travel (3.2mm) smaller keyboards require. The extra-slim keys have the flat, square shape you’d find on a Chiclet-style keyboard but are contoured in the center, though not nearly as much as you’d find on a full-size mechanical keyboard.


The SK621 connects directly with the USB cable or wirelessly via Bluetooth 4.0. In Bluetooth mode, you can connect up to three devices simply by flipping a switch on the side of the keyboard, then pressing and holding Fn + Z/X/C for three seconds to enter pairing mode. An indicator light on the Caps Lock key flashes blue three times when the device is successfully paired.

After that initial setup, you just use the same switch whenever you want to activate wireless mode and press Fn + Z/X/C to toggle to the desired device. The keyboard automatically switches to wired mode as soon as the cable connects to a computer.

sk621 02 us Cooler Master

You can apply presets to for static and dynamic color backlighting effects.

Typing feel

Like most compact keyboards, typing on the SK621 takes some getting used to. The keys themselves feel great, with decent travel, a satisfying click at the bottom of the stroke, and a springy rebound. They provide the tactile and audio feedback mechanical keyboard lovers prize.

But the reduced size of the keyboard was immediately noticeable. Each time I pressed a key, the side or pad of my finger came in contact with the edge of an adjacent key. Key discovery also requires time and patience, thanks to certain keyboard reconfiguration. The right Shift key, for example, has shrunken to normal key size, which resulted in my often overshooting it. The Delete key has been moved to the right edge of the keyboard under the return key.

This led to a rather cramped and confusing typing experience initially. After a week or so, I felt more acclimated to the layout, but I was never able to match my usual typing speed or accuracy.

on the fly controls Cooler Master

The SK621 offers plenty of "on-the-fly" control via key combos.

RGB lighting and macros

You can apply presets to modify the keyboard’s per-key backlighting. These range from static colors to dynamic effects that are activated by music or gaming actions. They can be activated with keyboard shortcuts—Cooler Master calls them “on-the-fly” controls—and many of the key combos are labeled on the keys so you don’t have to constantly consult the instruction manual. Downloading and using the Cooler Master Portal software is easier, though, and gives you more advanced controls.

The same is true for macro programming. They can be created to control backlighting, media playback, and key mapping using on-the-fly controls, though the software allows for more precise customization.


The Cooler Master SK621 is well made keyboard with plenty of eye candy for creative types. You’ll have to weigh how much productivity you’re willing to sacrifice for portability, though, because reduced speed and accuracy is the compromise you’ll make for the compact layout. I wouldn't recommend it as your daily keyboard, but it'll do for those times you’re away from your regular rig.