Features Two-layer Incorporate housing design Ball shape middle wheel Retractable and removable wire Customized colors and logos are accepted logo could be put into inside case for better protection Convenient for both travel and home users Perfect promotional gift item Various colors cover available Specification 3D optical mouse w/ball shape middle wheel Size: 8x6.5X2.0cm Super sensitivity and high accurate Resolution:1000dpi Compatible with Windows 95/98/NT/ME/2000/XP Simply plug and play Button life over1,000,000 times