C2G 28108 USB Cable - USB 2.0 One B Male to Two A Male Y-Cable, Black (6 Feet, 1.82 Meters) Increase the power running to a portable hard drive from your PC or Mac When a standard USB cable cannot transfer enough power to operate an external device, such as a portable 2.5in hard drive Simply plug this cable's USB B end into the device, and then plug the two USB A ends into open USB ports This cable is not designed to split USB signals to multiple computers. The two USB A connectors are meant to plug into USB ports on the same computer.