The WD Ultrastar DC HC520 12TB SAS 12Gb/s 3.5" Server HDD is a high-performance internal hard drive designed for server use. With a rotation speed of 7200 RPM and a storage capacity of 12TB, it offers fast data access and storage for demanding server applications. The hot swap feature allows for quick and easy replacement in case of a failure, making it a reliable choice for businesses and enterprises. Made by WD, a trusted brand in the industry, this Ultrastar DC HC520 model is compatible with SAS interfaces and is a top choice for those needing a high-capacity HDD for their server needs.