Connect two 3.5" SATA III hard drives to your computer through USB 3.0 with UASP in a RAID array, and charge or connect USB devices with the built-in 2-port USB 3.0 fast charge hub - The S352BU33HR 2-Bay RAID Enclosure lets you build an external RAID array using two 3.5” SATA hard drives, and add it to your computer through USB 3.0.For optimal performance from your SATA III drives, the external RAID enclosure supports a UASP-enabled USB 3.0 host connection, which performs up to 70% faster than conventional USB 3.0 when paired with a UASP compatible host controller. (See UASP testing results below for more detail).The RAID enclosure also lets you connect additional USB 3.0 devices to your computer, through an integrated 2-port USB 3.0 hub conveniently mounted on the front of the enclosure.