Sony Vaio VGN-NR123E USB Optical Mouse - VGP-UMS20 - VGP-UMS20/S Specifications : Operational system: Optical type sensor system Interface: USB and USB2.0 Button: 2 button systems (1 wheel attachments) Device driver: OS standard driver External size : Approximately width 52.6 height 26.7 depth 90.6mm Mass: Approximately 50g Cable length: Approximately 80cm Resolution: 800 counts (per 1 inches) Correspondence OS: Windows PC where Microsoft Windows Vista, Windows XP Professional and Windows XP Home Edition are preinstalled and equip the USB port (the IBM PC/AT compatible machine)