The SATDOCK4U2E e SATA & USB (Universal Serial Bus) 2.0 4-bay SATA hard drive docking station is a convenient, time-saving storage solution for 2.5-inch & 3.5-inch SATA hard drives (HDD) & solid state drives (SSD), allowing for up to 4 drives to be quickly connected to one or more host computers. The SATA hard drives can be paired & connected over two USB (Universal Serial Bus) 2.0 host connections (data transfer rates up to 480 Mbps), or each drive can be connected individually over a dedicated e SATA connection (up to 3 Gbps); this enables you to interface with a single docking station from multiple computers, for access to specific drive (s). All four drives can also be connected to a single computer over multiple cables, with dedicated bandwidth. The USB (Universal Serial Bus) 2.0 SATA hard drive docking station also features dual built-in, variable-speed 60mm fans that can be manually adjusted to keep each drive running cool, depending on the drives & operating environment, or turned off completely.