This product is either discontinued or we cannot get that from suppliers.
Dell 400-ATIN Hot Plug Hard Drive, Capacity 600GB, 2.5" 15,000RPM Hot Plug Hard Drive for R640/R740, Hot plug server drive, 12Gbps, Compatible with Dell servers.
Serial Attached SCSI (SAS) is the logical evolution of SCSI including its long-established software advantage and the serial physical connection interface.