Microsoft 3500 3-Button Wireless BlueTrack Scroll Mouse w/Nano Transceiver - Combines Optical Power w/Laser Precision! Microsoft Wireless Mobile Mouse 3500 General Features: Green and black design Two (2) Buttons Scroll wheel (acts as a third button) 2.4 GHz frequency Plug-And-Go Nano Transceiver Ergonomic design, perfect in either hand On/Off battery switch (located on bottom) Eight month battery life (operates on one (1) AA battery, included) Unit Dimensions: 1.75 x 2.25 x 3.76-inches (H x W x D, approximate)