Calibrate your CRT or LCD monitor with this simple to use USB colorimeter. Included with this small, lightweight measurement device is the install CD, a desktop cradle, extension USB cable and Quick Start Guide in original box. After calibration, room light is constantly measured when placed in desktop cradle. System requirements: Mac OS X (10.3 or higher), Windows 2000 or XP. Compatible displays: LCD, CRT, laptop (not suitable for multi-monitor systems).