HP 1TB 6G SAS 7.2K HDD 1 SAS 16 MB Cache 2.5-Inch Internal Bare or OEM Drives 605835-B21 Maximum External Data Transfer Rate - 600 Mbps (4.7 Gbps) Rotational Speed - 7200 rpm Hard Drive Interface - 6Gb/s SAS (Serial Attached SCSI)