Western Digital WD Red Plus WD40EFRX 3.5″ 4TB SATA 6Gb/s Hard Drive – Interface: SATA 6Gb/s – Formatted Capacity: 4TB – Form Factor: 3.5″ – Advanced Format – RoHS Compliant – Transfer Rate: Up to 150MB/s – Cache: 64MB – Performance Class: 5400 RPM – Load/Unload Cycle: 600,000 – MTBF: 1,000,000 Hours – Workload Rate: 180TB/Year – 3 Years Limited Warranty