At CES, Western Digital gave a sneak peek of their new My Book Thunderbolt Duo external RAID hard drives. Coming in 4 or 6 terabyte flavors, each unit features two HDD configured in RAID 0. Western Digital says individual drives should reach between 250MBps and 280MBps. During the CES Press preview, WD configured a RAID set with four My Book Thunderbolt Duo drives delivering speeds of 450MBps write and 760MBps read. Western Digital should be officially unveiling the My Book Thunderbolt Duo at Macworld this week.