Western Digital Ultrastar DC HC550 16TB 7200RPM SAS 12Gb/s 3.5″ HDD ‘ WUH721816AL5204 ‘ 0F38357 ‘ Refurbished Grade A ‘ 1-Year Warranty The WD Ultrastar DC HC550 (WUH721816AL5204 / 0F38357) is a 16TB enterprise SAS hard drive , purpose-built for high-capacity, high-availability data environments such as cloud, hyperscale, and scale-out storage. Featuring CMR technology , HelioSeal architecture , and a Triple Stage Actuator , this drive delivers optimal density and consistent throughput while reducing power consumption. Equipped with a SAS 12Gb/s interface , 7200 RPM spindle , and enterprise-class 2.5 million hour MTBF rating , the HC550 is ideal for storing mission-critical workloads at scale.