Description: Scientific encourages healthy neutral "handshake" wrist and arm positions for smoother movement and less overall strain. DPI button and 3D scroll wheel, left and right mouse buttons, page up and down dual buttons are very convenient while surfing Internet. 800 / 1200 / 1600 DPI Resolution Optical Tracking Technology provides more sensitivity than standard optical mice for smooth and precise tracking on a wide range of surfaces. Enters power saving mode (power is cut off completely) after some minutes idle, press right or left button for it to wake. Surface sanding process, excellent feeling. Specification: Product size: Approx. 123x65x82mm / 4.84x2.56x3.23inch Package Includes: 1 Piece Wireless Vertical Ergonomic Optical Mouse (2 AAA batteries not included) 1 Piece 2.4G USB receiver Note: 2.4G USB receiver color random delivery