QandA Q1. After I turn on the mouse, the red light flash and off A1. Please put USB receiver in computer when you text the mouse. Because only when mouse matched the USB receiver, it will work. Q2. What is the different between Soundand Silent A2. Silent version is mute version, it does not have sound when you press left and right button. Specifications: Item Name: 2.4G Wireless Mouse Buttons: 4 Buttons Ajustable DPI Switch: 800-2000DPI Verison: Silent(Mute) or Sound Color: Black or Gray or Green or Red WiFi Range: 10M Battery: 2 x AAA battery 1.5V [NOT work with 1.2V] (Not Included) Key Life: 10 million times Size: 115x80x40mm Compatible : Windows or VISTA or ... Package Included: 1 x Wireless Mouse( Without Battery ) 1 x USB Receiver Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.