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 Unique scroll Ring let you move up and down web pages or documents with ease; ambidextrous design works equally well for both right-handed and left-handed users Detachable Wrist rest softly cushions and cradles the hand and wrist in an ergonomic position for pain-free productivity during extended periods of activity on the computer Plug-and-play installation lets you get clicking and scrolling on your Mac or PC with fast, simple installation through the reliable wired USB connection — no batteries required. *USB-C to USB-A connector is needed for newer Mac products Free downloadable Kensington trackball works software provides a 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