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. The easy-to-reach hub also has fast charging capabilities; so you can charge your iPad; smartphone or other mobile devices as quickly as you would through a direct wall outlet connection. To help maintain safe operating temperatures for your hard drives; the 2-drive enclosure features a built-in cooling fan to ensure proper air circulation and prevent your SATA drives from over-heating. The enclosure features an integrated hardware RAID controller; which gives you the options you need to set up the array that best suits your storage application; including JBOD; Spanning; RAID 0; and RAID 1. To ensure compatibility with your computer system; the S352BU33HR supports all of the leading operating systems; including: Microsoft Windows® (8/7/Vista/XP/Server 2008/Server 2003); Apple® OSX (10.9/10.8/10.7/10.6); Linux; and Google Chrome OS™. The S352BU33HR is backed by a StarTech.com 2-year warranty and free lifetime technical support. Improved Performance with UASP UASP is supported in Windows 8; Mac OSX (10.8 or above); and Linux. In testing; UASP performs with a 70% faster read speed and 40% faster write speed over traditional USB 3.0 at peak performance. At the same peak in testing UASP also shows an 80% reduction in required processor resources. Testing results were obtained using an Intel® Ivy Bridge system; a UASP-enabled StarTech.com Enclosure; and a SATA III solid state drive.