3free 3F-MSM201/BS. Device interface: USB, Movement detection technology: Optical, Movement resolution: 800 DPI. Mouse weight: 60 g. Compatible operating systems: Windows 98 / 2000 / ME / NT / XP / VISTA, Minimum system requirements: IBM PC Pentium 400, Mouse dimensions (WxDxH): 88.5 x 50.8 x 34.8 mm