Scroll Ring and Medium BallSpin the dial to move up and down web pages or documents with complete ease. The blue 40mm ball has been specially designed with an absolute spherical hard surface for precise tracking and control.TrackballWorks CustomizationFree downloadable software provides an even more personalized experience giving you the ability to assign a wide variety of program functions to each of the 2 buttons as well as adjusting cursor and scrolling speedsOptical Tracking TechnologyProvides precise cursor movement for superior accuracy so you can get where you want on the screen quickly with less hand movement improving productivity and efficiencyDetachable Wrist RestSoft cushioning cradles the hand and wrist in ergonomic comfort for pain-free productivity during extended periods of activity on the computerAmbidextrous DesignWorks equally well for both right-handed and left-handed users to get the most out of their trackballPlug & Play InstallationQuickly get clicking and scrolling with fast simple installation through the reliable wired USB connection plus it doesnt need batteries- Award-winning Scroll Ring lets you scan up and down pages with ease- Medium 40mm ball is designed as a perfect sphere to provide exceptional precision- TrackballWorks software lets you customize the 2 buttons adjust cursor and scrolling speed- Optical tracking technology for superior cursor control and accuracy- Detachable wrist rest supports hand and wrist for ergonomic comfort- Ambidextrous design works equally well for both right-handed and left-handed users- Plug & Play installation via wired USB connection- PC and Mac compatible- Compatible with Windows 8