1. Laser Sensor from 800 dpi to 1600 dpi, adjustable by clicking simultaneously the 2 buttons for 5 seconds. -- 800 dpi: slow blinking -- 1600 dpi: super fast blinking 2. Powered by two AAA battery 3. Working distance: about 10m 4. PLL technology with automatic adjustment Plug & Play, driverless under Windows ME/2000/XP/Vista 5. ergonomic design for left hand and right hand. 6. Laser technology: Ensures accuracy and precision, works on any surface Including glass. 7. Scroll up and down directly without moving your hand. 8. Switch vertical to horizontal freely. 9. Button life: over 3,000,000 times. 10. Low power consumbation: A pair of 700MA battery can be used for more than 280 hours continuously