Scroll Ring and Medium Ball Spin 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. KensingtonWorks™ Customization Free 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 speeds.* *ChromeOS user can get HID functions for a trackball but will not be able to customize their device through KensingtonWorks. *Windows ARM-based computers are currently not supported. Please check back for future updates on compatibility. Optical Tracking Technology Provides precise cursor movement for superior accuracy so you can get where you want on the screen quickly with less hand movement, improving productivity and efficiency Detachable Wrist Rest Soft cushioning cradles the hand and wrist in ergonomic comfort for pain-free productivity during extended periods of activity on the computer Ambidextrous Design Works equally well for both right-handed and left-handed users to get the most out of their trackball Plug & Play Installation Quickly get clicking and scrolling with fast, simple installation through the reliable wired USB connection, plus it doesn’t need batteries SmartFit™ - Comfort Made Easy This product is designed to comfortably fit and be effective for users of all hand sizes.