Koolertron Mini 2.4G 19 Keys Wireless USB Numeric Keypad for iMac,Macbook, Laptop, Desktop/PC Computer Compatible with Windows and OS X System (Black) For the wireless receiver, easy to use, Plug and Play anytime and anywhere you want; Portable numeric keypad , allow yaou to deal with more professional data. " Scissor " button technology with moderate elastic keys , more comfortable. Using 2.4G frequency band,a access to keyboard, also with flashing LED lights; Compact and portable, rugged design; Need to control the keypad switch;the LED indicator alarms when the battery is less than 1.1V; System Requirements: IOS, Windows XP, Windows Vista or Windows 7, USB