Dual Wireless Technology - The ultimate in wireless freedom, allowing you to connect either via Bluetooth 4.0 LE that allows you to save a valuable USB port or through a highly reliable 2.4 GHz USB nano receiver KensingtonWorks Customisation - 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 4 buttons, as well as adjusting cursor and scrolling speeds DiamondEye Optical Tracking - Movement detection technology provides smooth, precise cursor control so you can get where you want on the screen quickly with less hand movement, improving productivity and efficiency Scroll Ring and Large Ball - Spin the dial to move up and down web pages or documents with complete ease. The red ball has been specially designed with an absolute spherical, hard surface for precise tracking and control Ambidextrous Design - Works equally well for both right-handed and left-handed users to get the most out of their trackball 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 System requirements - Compatibility with USB receiver: Windows 10, 8.1, 8, 7 and Mac OS X 10.8 and later / Compatibility with Bluetooth 4.0 LE: Windows 10, 8.1 and Mac OS X 10.8 and later