A4Tech OP-620 . Device interface: USB, Movement detection technology: Optical, Movement resolution: 620 DPI. Mouse dimensions (WxDxH): 62.9 x 118.8 x 35.3 mm, Mouse weight: 86 g. Compatible operating systems: Windows 98/ME/2000/XP (X64)/2003 (X64)/MCE 2005/Vista X86/X64