WD Re 4TB | WD4001FYYG | 7.2K RPM Class SAS 6Gb/s 32MB Cache 3.5 inch Data Center Capacity Hard Disk Drive Capacity: 4TB, for your data storage needs SAS 6Gb/s interface optimizes burst performance Spindle Speed: 7.2K RPM for improving data transfer rate Form Factor: 3.5 inch and cache: 32MB Does not work with Dell MD Powervault series