The key cluster module attaches to the left keyboard half, and it features three regular keys, two buttons, and a mini trackball, which can also be pressed - acting as an extra button. All of the keys and buttons are fully configurable. Following is a demonstration of the key cluster and trackball modules.
The key cluster module features hot-swap sockets, per-key RGB backlighting, and double-shot PBT keycaps.
Every UHK module is compatible with the UHK 60 and UHK 80.
