Dynex DX-PHD35 3.5" External USB 2.0 Hard Drive Enclosure 3.5" hard drive enclosure: Supports up to 750GB PATA/EIDE hard drives. High-speed USB 2.0 interface: USB-powered, so an AC adapter is not required for most computers. One-touch button: Lets you easily back up, restore or synchronize your files. Plug-and-play design: For ease of use. Compatible with PC and Mac: For flexible options and use with more than 1 computer.