Add an e SATA port to a desktop computer through a PCI Express slot. This e SATA Controller Card turns a PCI Express (1x) slot into an external SATA port, to provide a quick & hassle-free external storage solution. Supporting SATA 300 (SATA II) hard drives (backward compatible with SATA /150) & data transfer rates of up to 3 Gbps, this PCI Express e SATA Controller Card is the perfect solution for upgrading existing e SATA capability, or simply adding an external SATA port to a PC or Mac desktop computer. Using a native PCI Express single chipset, the controller card provides enhanced compatibility, reliability & performance for your external storage needs. The controller card also features port multiplier support with command based switching for connecting multiple external hard drives to a host computer through one e SATA connection. The PCI Express e SATA Controller Card also features an internal SATA port, which could be used for a conventional (internal) SATA drive installation. Please note that the internal SATA port can not be used at the same time as the external SATA port.