If there’s one thing you should know about Thunderbolt connectivity, it’s this: Thunderbolt transfers data fast. Very fast. 10Gbps fast. Twice that of USB 3.0’s 5Gbps speed. If you’re looking for an external hard drive that can transfer data at those speeds via dual Thunderbolt ports, includes RAID support and provides up to 2TB of storage space, the Western Digital 2TB My Book VelociRaptor Duo Thunderbolt Desktop Hard Drive delivers.