The Extreme FireWire Reader is a high performance reader, which provides you a complete digital system solution for your photography needs. It offers the performance requirement, up to 40MB per second sequential read and write. It has one slot for CF (Type I and II). It supports FireWire 400 & 800 connectivity on both Windows and Macintosh Operating Systems. It plugs and plays with no external AC power. The Extreme FireWire (FW) Reader supports the Extreme IV CF (Type I and II) cards.