Seagate 500GB Momentus Thin SATA 3Gb/s 16MB Cache 2.5-Inch Internal Notebook Hard Drive (ST500LT025) 7mm z-height form factor enables thin chassis design for all segments of laptop computing Seagate SmartAlign technology provides a transition to 4K sectors without the need for software utilities. Seagate Self-Encrypting Drives (SED) deliver government-grade encryption without performance degradation-protecting your data where it lives. Features 16MB cache on a 5400rpm, thin drive