1TB 7200RPM USB 2.0, Firewire 400/800 (A/B) DualDrive PRO External Hard Drive...550 ProDrive has not one but two high performance hard disks inside its striking aluminum enclosure. The built in RAID 0 function combines them into one ultra-fast data storage machine. Data is distributed across both hard disks simultaneously, achieving faster transfer rates and shorter access times. AcomData's hardware-based RAID 0 controller works automatically, behind the scenes. There's no software to install, and unlike the software-based RAID schemes it does not depend on your computer's processor. The result is full capacity, super-charged performance, and no compromises