Turn 4 SATA hard drives into external RAID storage, connected through USB (Universal Serial Bus) 3.0 or e SATA Support for up to 4 drives provide large amounts of storage with a choice of high speed interfaces from USB (Universal Serial Bus) 3.0 or e SATA The removable front cover & accessible drive bays allows drives to be replaced easily in case of failure or a system upgrade Built-in support for numerous RAID modes for most personal/business needs & an 80mm controllable cooling fan to keep drives from overheating The SAT3540U3ER 4-Drive USB (Universal Serial Bus) 3.0/e SATA to 3.5" SATA RAID Enclosure is a high-performance external RAID storage solution that supports up to 4 high capacity (tested with up to 4TB per bay) 3.5-inch SATA hard drives over a USB (Universal Serial Bus) 3.0 or e SATA connection. The 4-bay RAID enclosure can be connected to the host/source computer through USB (Universal Serial Bus) or e SATA & automatically builds your SATA RAID array based on your selection (Spanning, RAID 0, RAID 1, RAID 1+0, RAID 3, & RAID 5 supported), delivering a simple, yet flexible external storage solution. Designed for convenience, the enclosure features front panel LED indicators that provide RAID information & simple hard drive status & activity monitoring. The enclosure also features a built-in, 3-speed 80mm fan with automatic or manual controls that enable you to customize the speed of the fan as necessary to ensure suitable operating temperatures for optimized drive performance. Whats in the box Four drive HDD enclosure Hard Drive Handle USB (Universal Serial Bus) 3.0 Cable e SATA Cable Screw driver & screw kit Power Cord (NA/ UK/ EU) Universal Power Adapter Instruction Manual