Add an eSATA port to a desktop computer through a PCI Express slot. This eSATA Controller Card turns a PCI Express (1x) slot into an external SATA port, to provide a quick and hassle-free external storage solution. Supporting SATA 300 (SATA II) hard drives (backward compatible with SATA /150) and data transfer rates of up to 3Gbps, this PCI Express eSATA Controller Card is the perfect solution for upgrading existing eSATA capability, or simply adding an external SATA port to a PC desktop computer. Using a native PCI Express single chipset, the controller card provides enhanced compatibility, reliability and 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 eSATA connection. The PCI Express eSATA 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.