The SDOCK2U33RE Dual 2.5/3.5" SATA HDD/SSD duplicator dock lets you duplicate/clone an existing hard drive without the use of a host computer system -- or dock & swap drives from your desktop or laptop computer simultaneously, using a single USB (Universal Serial Bus) or e SATA port. Versatile Features The SDOCK2U33RE offers convenient dual-function performance. As a hard drive duplicator, the SDOCK2U33RE lets you create an exact sector-by-sector clone from one hard drive to another, including partitions & boot sector information -- ensuring data integrity & consistency for sensitive operations, such as data recovery. As an external hard drive dock the SDOCK2U33RE lets you connect your drives through either e SATA or USB (Universal Serial Bus), with each drive slot individually supporting high capacity 2.5/3.5" hard drives or solid state drives, tested up to 4 TB. Fast Performance With support for SATA III (6 Gbps) you can maximize efficiency with duplication speeds up to 22 GB per minute, & e SATA docking speeds up to 6 Gbps. The Dock can also be connected through USB (Universal Serial Bus) 3.0 with UASP for transfer speeds up 5 Gbps (70% faster than conventional USB (Universal Serial Bus) 3.0). See our UASP testing results below for further details.