Wireless Number Pad N305 is designed for use with notebooks and offers advanced 2.4 GHz wireless connection and sturdy design so you can use it anywhere. Simply plug the receiver into a USB port to begin. Wireless receiver remains plugged so the number pad is always ready for use. Easily add compatible wireless mice and keyboards (sold separately) to the same wireless receiver. Advanced 2.4 GHz wireless connectivity delivers the reliability of a cord, cordless convenience, fast data transmission, virtually no delays or dropouts, and 128-bit AES encryption. An indicator light helps you keep an eye on your charge level. The battery life lasts three years. Number pad requires a USB port, Windows XP, Windows Vista or Windows 7, and Internet connection for software download. Number pad includes Logitech Unifying receiver and two AAA batteries.