This 1 Port eSATA ExpressCard adapter lets laptop users experience the high performance capability of eSATA storage for data transfer rates of up to 3Gbps, as well as port multiplier capability with command-based switching for connecting multiple external hard drives to a host PC or Mac notebook through a single eSATA connection. Using a native PCI Express single chipset, the eSATA controller provides enhanced compatibility, reliability and performance for your external storage needs. The adapter features aslim ExpressCard design, that allows the adapter to recess completely into the 34mm ExpressCard slot and lets you to leave it installed in the slot during transporting without worrying about damaging the card or connection port.