Ergoguys CST1550 Black USB or PS/2 Wired 1600 dpi Ergonomic PC-Trac Trackball Hand Orientation: Both Hands Maximum dpi: 1600 dpi Operating System Supported: Windows 98SE, ME, NT4 2000, XP and Vista as well as MAC OS9 MAC OSX and all USB 1.1 HID 1.0 compatible operating systems such as Linux and Sun Solaris |