Western Digital External Hard Drives
FireWire, USB and eSATA

Western Digital My Book Studio External Hard Drives - Quad Interface:
eSATA, FireWire 800, FireWire 400 & USB 2.0

Western Digital My Book Premium Edition External Hard Drives - Dual Interface: FireWire 400 & USB 2.0

Western Digital My Book Pro Edition External Hard Drives - Triple Interface: FireWire 800, FireWire 400 & USB 2.0

1000GB Western Digital My Book Pro Edition II External Hard Drive - Dual drive system, use as RAID 0 for capacity (1000GB) or RAID 1 for data protection (continuous backup of one 500GB drive to another)
1500GB Western Digital My Book Pro Edition II External Hard Drive - Dual drive system, use as RAID 0 for capacity (1500GB) or RAID 1 for data protection (continuous backup of one 750GB drive to another)
2000GB Western Digital My Book Pro Edition II External Hard Drive - Dual drive system, use as RAID 0 for capacity (2000GB) or RAID 1 for data protection (continuous backup of one 1TB drive to another)