Cobra II mouse is an upgrade version of Cobra I mouse. Product Specification 1. Optical type: Red wave 2. Operation voltage: DC 5V+-5% 3. Size: 128 x 63 x 40 mm (5*2.5*1.6 inches) 4. Frame Rate: 4000 Frame / sec 5. Acceleration: 15g 6. Interface: USB 7. Weight: 130g (4.58oz) 8. Buttons: 6 9. DPI: adjustable 400 / 800 / 1600 10. Switch Life: 3,000,000 times 11. Cable length: 1.8 meter 12. Product Compatibility: Windows 98 / 2000 / ME / NT / XP / Win 7 / Vista / OSX 10.2~