LaCie has announced today that its first Thunderbolt device, the Little Big Disk Thunderbolt external drive, is now available for purchase. The drive was announced all the way back in February for a summer launch, and now it is finally arriving at Apple Stores – though only the HDD variant. Its dual-disk design that can be configured in either RAID 0 or RAID 1, and comes in two configurations: 1TB with 7200rpm speeds, or 2TB with 5400rpm disk speeds.

In terms of performance, the new drive boasts read speeds of up to 190 MB/s, but according to LaCie users can daisy chain several Little Big Disks to maximize Thunderbolt's capabilities and reach transfer rates of 800 MB/s. The company will be releasing an SSD version of the drive in October that increases read speeds to over 480 MB/s.

Its rugged aluminum protective casing measures just 1.6 x 5.5 x 3.3 inches and weighs about 1.4 pounds. The drive is compact and light enough to carry in a backpack, but it's not exactly portable, as you'll need to a separate AC adapter to power it. The drive comes with a tiny fan in the back that emits almost no noise during operation.

Priced at $400 for the 1TB version and $500 for the 2TB model, the new Little Big Disk is not exactly cheap. Then again, your only other Thunderbolt-equipped storage option is the 4TB, $1,000 Promise Pegasus that debuted in June.