WD Ultrastar SATA Series hard drives are built from the ground up to be an ultra-robust storage device. Designed with a workload rating up to 550TB per year, Ultrastar drives are the perfect choice for business-critical applications like enterprise servers, storage subsystems, surveillance analytics and industrial environments. Ultrastar quality and reliability is delivered under both the Western Digital brand and the HGST brand. Higher capacities are made by HelioSeal technology, delivering the lowest $/TB and Watts/TB to minimize total cost of ownership (TCO). Lower capacity drives are built using traditional air-filled technology, ideal for users looking for lower acquisition cost.