Aopen W-23B - Scroll Wheel - PS/2-3 Buttons - 520 Dpi Specification Model W-23B Interface Protocol: PS/2 Switch Life: 1,000,000 cycles Current Consumption: 20mA max@5V Button: 3 buttons(2 in Top,1 in Wheel) Cable Length: 180 cm (70") Mouse Resolution: 520 dpi Mechanical Life: 300 miles Operating Systems: Windows 95/98/Me/NT/2000/XP and beyond Packing: AOpen Retail Box Certifications: FCC, CE, TUV, VCCI, UL, CUL, CSA - NOTE: THIS PRODUCT CANNOT BE SHIPPED TO MASSACHUSETTS OR DISTRICT OF COLUMBIA (WASHINGTON, D.C.)