My housemate and I both had a CK350. After about two months of use the Windows key stopped working, and then after another month the entire keyboard failed. It can still recognise key presses (FN, hard resets, etc), however will not send it to the PC. I've tried it on 4 different PCs, including Linux and OSX and it does not work. My housemate's CK350's Windows key now also does not work. The caveat to the nice design, materials, keys and cheap price is subpar wiring or integrated PCB failing.