This is a 2.4GHz wireless mini QWERTY keyboard and trackball combo, with USB interface receiver. Plug and play, simple and smooth. The mini keyboard ensures convenient typing, and you can control your devices on your couch. Wireless Mini Keyboard: The mini keyboard ensures convenient typing with classic keys and multimedia keys, and you can control your devices on your couch. Optical Trackball : Optical-sensor trackball controller strengthens the touch experience and ensures flexible control of the lap or HTPC when there is no . Scroll Wheel Design: The bottom right corner of the keyboard has the left and right keys and scroll wheel which can randomly turn between two directions. Wide Application: Compatible with Android, Windows and Linux OS. Suitable for XBOX 360, for PS3, HTPC / IPTV, Android TV Box, Lap, projector and so on. Specifications: Model Number: E30 Connection: 2.4G wireless Working Distance: within 10m Amount of keys: 79 keys + Scroll Wheel + Trackball Button Life Time: 8 million times Tracking method: optical trackball DPI: 1200 Battery: 2 * AA battery (not included) Color: Black, Silver (Optional) Main Item Size: 26.0 * 11.8 * 2.5cm / 10.23 * 4.64 * 0.98in Main Item Weight: 223g / 7.87oz Package Size: 28.0 * 12.6 * 3.5cm / 11.02 * 4.96 * 1.37in Package Weight: 280g / 9.89oz Package List: 1 * Keyboard 1 * USB Receiver 1 * User Manual