It spins like a knob. It clicks like a mouse. But it’s so much more.

System Requirements:
• Mac: Mac OS X 10.3.9 or greater, and a USB port
• PC: Windows XP, or Vista, USB port

Technical Specifications:
• Height: 1.3 in. (33.4 mm)
• Diameter: 2.1 in. (53.8 mm)
• Weight: .26 lb. (.11 kg)
• Cable Length: 22″
• USB Extension Cable Length: 40″

http://store.griffintechnology.com/desktop/powermate