Farassoo Mouse FOM-690RF: High definition optical technology with body rubber coated Space saving on desk, ideal for travelers Scrolls two ways for greater efficiency Comfortable in either hand Auto power off for preserving battery life when receiver snaps in to mouse With 2×AAA rechargeable batteries 2.4 GHz frequency micro receiver ensures high-quality connectivity Specifications: Motion Resolution: Buttons: Type: Operation distance: Interface: System Requirements: Dimensions: 800 dpi(Optical) 3 Wireless 7m PS/2, USB, Combo (Optional) Windows 9X or higher 95(L) x 62(W) x 34.5(H) mm