Premium quality USB Wired Optical Mouse. Ergonomic design provides better support for your palm,wrist,finger-joints and will bring endless comfort for many working hours. 3-button mouse: Left and Right buttons and roller (with encoder and mechanical roller). Left and Right buttons are convenient for users who require precise positioning and use functions such as opening,closing, select files. Scroll buttons are used for flexible drive roller and can be implemented in the specific software for up and down or automatic functions.