SATA III cable is designed to connect motherboards and host controllers to internal Serial ATA hard drives and DVD drives, quickly upgrading your computer for expanded storage. Please be kindly noted that this cable does not provide power for your hard drive. It must be powered separately. The latest SATA Revision 3.0 allows for data transfer speeds of up to 6 Gbps, 2x faster than SATA II, backwards compatible with SATA I and SATA II. Data transfer speed is limited by rating of the attached equipment.