What's NKR? None of the things on Google looked right.
N - Key Rollover. Basically it allows you to hold an undefined (N) number of keys at the same time and have them all register simultaneously on the computer. It's really importing in, say, fps's where you are holding maybe shift for crouching, w and a for movements, and try to throw a grenade. Without NKR, you may stand up to throw the grenade, with it, you would stay crouching.