RTIV435SMR5 RAID Tower IV (black color) with 1 4X1 eSATA/USB 2.0 Hardware Port Multiplier installed. Install up to four 3.5" SATA hard drives of any capacity (drives not included). Drives are added or removed like tape cartridge from each drive bay with no special tool required. Connect to system via USB 2.0 or eSATA port (connecting cables included). Drives can be configured via a rotary switch on the back. OS independent, can be used on any system. RAID diagnostic via LED lights. For more detail, please visit http://www.addonics.com/products/raid_tower/raid_tower_rtiv.asp