CK285B 2.4GHz wireless transmission high precision optical mouse. Zero-delay and 1600DPI optical engine. Scroll wheel for easy navigation. No mouse pad required， gives smooth， precision motion on virtually any surface. Agree with the palm arc， comfort for either hand user. Easy plug and play. Ergonomics design. 0-10 meters working range. Work with two AAA alkaline batteries (not included). With power switch， more economical and convenient for power command.