The Kensington Orbit™ Wireless Mobile Trackball offers a precise, compact & versatile experience with a centered-ball design. With no wires to tie you down, the 2.4 GHz wireless with storable nano receiver works wherever you do, at your home or office. & the unique touch scrolling lets you glide effortlessly through web pages & documents. Features A distinctive centered-ball design gives you more comfort & precision Ambidextrous design for left or right-handed users Compatible with Windows 7, Windows XP, Windows Vista, & Mac OS X. Trackball Works™ software downloadable from www.kensington.com Nano Wireless USB (Universal Serial Bus) reciever stores inside mouse battery compartment when travelling On/ Off switch helps prevent accidental battery drain Professional matt black high gloss black finish Requires 2 x AA batteries (included) Secure 2.4 Ghz wireless technology reduces risk of interference & is ideal for office environments Two customizable buttons with Kensington Trackball Works™ software Unique touch scrolling lets you glide effortlessly through web pages & documents USB (Universal Serial Bus) Plug & Play