Griffin Technology PowerMate Bluetooth Controller

Spin and click your way through your favorite applications with the PowerMate USB Controller from Griffin. This sleek device connects wirelessly to your Mac over Bluetooth 4.0 and allows you to use the spinning, clicking knob for anything from controlling your volume, to scrolling through webpages, to jogging and shuttling through audio and video files. The bottom of the PowerMate glows with a gentle blue light, and the unit runs on two AAA batteries, which are included.