Ten meters is the wireless range. 10. Keypad for numbers Controls for Music Limit of 5 million keystrokes (number lock key excluded) Type of key: deep-profile Resistant to spills tested in a restricted environment with a maximum liquid spillage of 60 milliliters. The keyboard should not be submerged in liquid. An alkaline battery (two AAA batteries) Sensor Technology: Optical Tracking That Is Smooth There are three buttons (left/right and middle clicks). Line-by-line scrolling Scroll Wheel: Optical, indeed Two Alkaline batteries (AA batteries)