4TB Hard Drive Western Digital - WD40EFRX WD Red NAS Internal Hard Drive - 4TB Capacity - 3.5 Inch - SATA 6 Gb/s - 64MB Cache - Compatible with WD My Cloud EX2 and EX4 Western Digital Red (WD40EFRX), specifically designed for Network Attached Storage (NAS) systems operating 24/7 in homes and small offices. Key Specifications Storage Capacity: 4TB (4.0TB). Interface Type: SATA 6 Gb/s. Cache: 64MB. Rotation Speed: 5400 RPM Class with IntelliPower technology to reduce power consumption and noise. Form Factor: 3.5 Inch. Technical Features NASware 3.0: Advanced WD technology to improve NAS compatibility, reduce RAID array crash issues, and enhance performance in continuous operation environments. Reliability: Designed to handle workloads up to 180TB per year with a Mean Time Between Failures (MTBF) of up to 1 million hours. 3D Active Balance Plus: Technology that helps protect data from excessive vibration and noise within multi-drive storage systems. Cooling: Features low operating heat, making it ideal for small, poorly ventilated enclosures. Ideal Uses NAS systems with 1 to 8 drive bays. Storage and sharing of multimedia files (4K photos and videos). Data backup for home and small offices. Selling to the highest bidder, God willing