Another reason for the price is the fact that its a RAID device, here's what that means:
"RAID stands for Redundant Array of Inexpensive Disks and at the simplest level it combines many disks into one logical drive."
One of the cooler features of the HDD is that you can switch between RAID 0 and RAID 1, the difference?
"RAID 0: Striped Set -- A RAID 0 setup splits data evenly across two or more disks. It is important to note that RAID 0 was not one of the original RAID levels, and is not redundant. If one drive goes down your server will need to be restored from backup.
RAID 1: Mirrored Set -- A RAID 1 setup creates an exact copy (or mirror) of data on two or more disks. A typical setup just has two drives that are setup to mirror data. If one drive goes down your server will still be functional until a scheduled drive replacement can be installed."
Switching the device to RAID 1 halves the available storage space but doubles the level of data protection as all your data is duplicated.
The deal is available here
Thanks to 45th Parallel Internet Services for providing their explanation of RAID systems.