IBM 81Y9794 Hard drive - 2 TB - hot-swap - 3.5 inch - SATA-600 - NL - 7200 rpm - for System x3300 M4 (3.5 inch ), x3500 M4 (3.5 inch ), x3550 M4 (3.5 inch ), x3630 M4, x3650 M4 (3.5 inch )