Secure Digital (SD) Multimedia Mobility Kit of Sandisk 4GB microSDHC, SD adapter and USB (Secure Digitial) SD High Speed Yellow Color Card Reader / Writer Kit include 3 items: 4GB Class 4 microSDHC memory card, SD adapter and USB Secure Digital card reader/writer System Requirements - Windows Vista (ReadyBoost not supported), Windows 2000 SP3 and SP4, Windows XP SP1 and SP2, Mac OS 10.2.x and above Reader is USB 2.0 interface (USB 1.1 compliant) LED indicator light on reader to indicate USB connectivity Speed performance rating: Class 4 Compatible with microSDHC devices