HGST Ultrastar 3.5" Enterprise 7200RPM Hard Drive - 4TB (H3IK40003272SN) the world's first 4TB 7200 RPM hard drive with a 2.0 million hours MTBF specification 3.5-inch Enterprise SATA Hard Drive Colossal Capacity for RAID and NAS solutions 24x7 accessibility for enterprise-class, capacity-optimized applications