Internal Sata To Esata Adapter for Mac Pro Incl Cables & Bracket (Discontinued by Manufacturer) Adds two eSATA ports to your Mac Pro or PC with motherboard SATA Enables you to connect up to two external hard drives using the eSATA interface for faster performance than FireWire or USB 2.0 Connects to your computer's logic board; does not impact its PCI Express bus configuration or performance