Optimal Shop Ultrathin Silent No-Light 1600DPI Bluetooth V3.0 Wireless Mouse - Black (2 x AAA) Adopts advanced Bluetooth 3.0 technology, transmission distance is up to 10m (3.3ft) No USB receiver is needed if your computer possesses Bluetooth function. But if your computer does not have this function, please take a Bluetooth dongle first. (Bluetooth dongle is not included in this item.) Designed with a DPI key to adjust its operation speed (800dpi, 1200dpi, 1600dpi). Operating instructions: 1. Please ensure that your equipment you will connect support bluetooth function. 2. Place AAA batteries into mouse, toggle ON/OFF key to ON and press on left key, roller key and right key at the same time, waiting for the indicator light to alternate between red and blue. Then click search and add on the equipment you will connect. Note: the mouse battery 2 * AAA batteriesmust keep enough power, performance is strong. If you for any reason are not happy with any product supplied , please do not hesitate to contact us and we will do our best to solve your problem .