The S3520WU33ER 2-Bay RAID Enclosure with UASP enables you to build a secure external RAID array with two 3.5” SATA hard drives, connected to your computer through an available USB (Universal Serial Bus) 3.0 or e SATA port. For fast performance & efficient data transfers the enclosure supports SATA III transfer speeds -- up to 6 Gbps when connected through e SATA. The versatile RAID enclosure can also be connected through USB (Universal Serial Bus) 3.0, with support for UASP, performing up to 70% faster than conventional USB (Universal Serial Bus) 3.0 when paired with a UASP-enabled host controller. See our UASP testing results below for further details. This versatile external RAID enclosure features a built-in hardware RAID controller, supporting JBOD, Spanning, RAID 0, and RAID 1 -- to achieve greater drive capacity, or secure data redundancy. To maximize both durability & reliability, the enclosure features high-quality aluminum construction with a built-in fan for better ventilation.