Optical Wireless Nano Mouse Model: MP2800BLACK. Features: Optical Sensing Technology, Built-in Scroll Wheel, Automatic Wireless Synchronization , 2.4 GHz Wireless Nano Receiver with Adjustable Height Design. Package Contents: Optical Wireless Nano Mouse, Nano Receiver,User"s Manual and Warranty Information. System Requirements: PC & MAC Compatibles Windows 2000, XP and Vista Mac OS 10.3 and above. An Available USB Port and 2 AA Batteries