1、USB Receiver: This wireless number pad comes with USB receiver to provide 2.4G wireless connection which is stable and quick in response. 2、Concave Keys: This numeric keypad adopts 18 keys in concave style, offering most comfortable tilt angle and reducing pressure on wrist. 3、Widely Compatible: This wireless keypad is suitable for Win 98/95/NT/for ME/2000/for Win XP/for Vista/7.0/8.0 or higher, compatible with laptop and desktop. 4、Battery Powered: This number pad is plug and play, and it's powered by 1 piece of AAA battery(battery no included). 5、Compact Design: This wireless numeric keypad adopts ABS material which offer great comfortable touch and precise control. Compact design, small, light and portable.