The Xbox 360 uses standard 2.5" SATA hard disk drives (HDDs) held within custom enclosures. These units have a custom connector to facilitate connection to the Xbox 360 and the drives themselves feature custom firmware (making stand-alone drives incompatible). The drives are detachable, making it possible to move data from one console to another, and to upgrade the size of drive on a console. The hard drives themselves are manufactured by various companies, including Fujitsu, Seagate, Samsung, Hitachi and Western Digital. Certain Western Digital hard disk drives can be modified with a program called HDDHackr to be used with the Xbox 360.