For System x3550 M5 x3650 M5Specifications:Category IBM HardDriveSub-Category 7.2KGeneration G2HS LFF SASPart Number 00FN208Products ID 481542Capacity 4TBInterface Serial Attached SCSI 3Enclosure InternalHDD Form Factor 3.5 inchSpindle Speed 7200RPMCompliant Standards S.M.A.R.T TechnologyData Transfer Rate 1.2GB/sHot Swap Yes