WD 0B35950 HGST Enterprise HDD, 4TB, 7200 RPM, 256 MB Cache

This Ultrastar DC-series data center hard drive (4TB) is an enterprise/OEM-class HDD built for hyperscale and data center storage, where total cost of ownership drives every design decision. It uses helium-sealed (HelioSeal) construction for better power efficiency per terabyte and, on higher-capacity models, Energy-Assisted Magnetic Recording (EAMR) to pack more data onto each platter without sacrificing reliability. It's built for continuous, high-duty-cycle operation in servers, RAID arrays, and dense storage racks, with the broad platform validation and vibration tolerance expected of enterprise/data-center drives. As an OEM part, it ships without WD's retail packaging but carries the same data-center-grade engineering as WD's branded Ultrastar line. Model 0B35950 specifically ships with 7200 RPM, 256MB cache.