Genius Silent Ergo 8200S Black Genius Wireless Silent Mouse RF Frequency 2.4 GHz Sensor engine BlueEye Resolution (DPI) 1200 Number of buttons 5 (Left, right, middle button with scroll, page up, page down) Battery type AA Weight (g) Approx. 65 g Dimensions (W x H x D) mm 73.5 x 107.8 x 40.6 mm