The Kensington Orbit(TM) Wireless Mobile Trackball offers a precise, compact and 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. And the unique touch scrolling lets you glide effortlessly through web pages and documents. Features A distinctive centered-ball design gives you more comfort and precision Ambidextrous design for left or right-handed users Compatible with Windows(R) 7, Windows(R) XP, Windows Vista(R), and Mac OS(R) X. Trackball Works(TM) software downloadable from www. kensington. com Nano Wireless USB 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. 4Ghz wireless technology reduces risk of interference and is ideal for office environments Two customizable buttons with Kensington Trackball Works(TM) software Unique touch scrolling lets you glide effortlessly through web pages and documents USB Plug & Play