TeckNet Econo 2.4G Wireless Mouse with Nano Receiver, 18 Month Battery Life,2000 DPI 2 Adjustment Levels 2.4GHz Wireless - A more secure and precise experience than the traditional FM radio system with an increased working distance of up to 15m TeckNet Tru-Wave technology provides precise, smart cursor control over many surface types. TeckNet Co-Link technology  after pairing theres no need to re-establish pairing after a signal loss or shutdown Tiny USB Nano style receiver plugs into your PC and can stay there. Select your preferred cursor speed; 2000/1500/1000dpi, Plug & play - no need to install a driver. Energy Efficient: The auto power-off function switches off the mouse when the USB Nano receiver is disconnected, or the PC is switched off to give 18 months battery life from 2 x AAA battery(not included). Features a battery level indicator.