This is a USB-connected Realforce keyboard. I disassembled it completely and cleaned it once, but it had been left untouched for a while, so some dust has accumulated in the meantime. I will clean it as much as I can see before shipping. As shown in the second photo, there is some discoloration around the numeric keypad. I tried to remove it when I disassembled the keyboard, but I couldn't. Please be aware that this is an older item. I confirmed that all keys could be entered when I cleaned it previously. Please check the photos for other conditions.