Sans Digital TowerRAID TR4UT-BP 4-Bay 3.5-Inch USB3.0 eSATA External Hard Drive RAID Enclosure with 6G PCIe 2.0 HBA Form Factor: Compact Tower HDD Trays: 4 x 3.5 inches Hot-Swappable Drive Trays RAID Level: 0, 1, 10, 3, 5, Clone (N-way Mirror) with Hot Spare, and JBOD Maximum Capacity: 12TB Host Interface & Transfer Rate: USB 3.0 (backward compatible with USB 2.0) and eSATA Drive Interface: 4 x 3.5 inches SATA/SATA2 Cooling Fan: 3.15-Inch Ball Bearing Fan Status Indicators: Activity with Fail and Power LED