Almost all the K90’s keys are made by the Cherry Corporation, which dominates the mechanical key switches market. Corsair uses the Cherry MX Red model and mixes it with some regular (and less expensive) membrane keys for the 18 macro (G1-G18), function (F1-F12), ESC, PrtScn, Scroll Lock, Pause/Break and page navigation keys.
On the right upper corner, the user can find the button that controls the intensity of the blue backlight (in steps from zero, 33%, 66% and full illumination), the Windows key lock button, multimedia controls, and a volume control roller. There are three small white LEDs for the CAPS, scroll and number locks keys.
The K9 features a removable full length rubberized wrist rest. The user has to snap it on two front latches and then screw it in on both sides, so the whole keyboard ends up being very solid and stable on the table.
On the upper edge there is a USB port for a mouse (or a USB headset, perhaps). The cable features two USB connectors, and one of them is a USB pass-through to feed the port on the upper edge. It’s nice that the connectors are blue so they’re easy to spot behind the usual cluster of cables behind the PC.
The underside comes with two retractable feet and two latches for the wrist rest.