500GB, 7200 rpm, SATA
DS4700 Express Models and DS4000 EXP810 Storage Expansion Units accept up to sixteen 500 GB SATA E-DDMs. You can use this E-DDM to increase the physical storage capacity of these models up to 8 TB per enclosure.
IBM 500GB SATA. Hard drive size: 3.5", Hard drive capacity: 500 GB, Hard drive speed: 7200 RPM, Hard drive interface: Serial ATA, Device type: HDD