... waterproof and dustproof features superior to a purely mechanical keyboard switch; key operation force of 60 ± 20cN; ... WinME, Win2000, WinXP operating system..Programming features All keys can be programmed, each key is programmable up to ... , X-, P, L stalls Z keys: Z, X, P, L, stalls X-keys: X, P, L stalls life ... ° C; Operating Humidity 20% - 90%;atmospheric pressure 86 - 106 kPa programmable keyboard