The Super-Speed USB 3.0 dual-bay dock is the easiest and most cost-effective way to access any two hard drives. This hot-swappable dock is perfect for accessing bare 2.5" or 3.5" SATA drives**. They will be read separately on your computer as JBOD (Just a Bunch Of Disks). The new USB 3.0 interface features maximum speeds of up to 5 Gbit/s*, which is equivalent to more than 600 MB per second! This is fast enough to handle some of the fastest hard drives. Windows XP/Vista/7 + (32 and 64 bit). Mac OS X 10.4.8 and later. Hard drive not included.