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) / Sound Color: Black / Gray / Green / Red WiFi Range: 10M Battery: 2 x AAA battery 1.5V [NOT work with 1.2V] (Not Included) Key Life: 10 million times Size: 115 x 80 x 40mm Compatible : Windows / VISTA / ... 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.