Power-Disable Model - With new power-disable pin (pin3) feature, not compatible with legacy systems and older PSUs MASSIVE CAPACITY, POWER EFFICIENCY AND RELIABILITY - Designed to handle workloads up to 550TB per year, Ultrastar DC HC520 is an 12TB HDD that helps address economic and access requirements of many traditional IT workloads. DATA DURABILITY AND SECURITY - Ultrastar DC HC520 helps protect data from unauthorized use by offering security and encryption options. HGST QUALITY AND RELIABILITY - The Ultrastar DC HC520 extends Western Digital's long-standing tradition of reliability leadership with a 2.5M-hour MTBF rating. MAXIMUM FLEXIBILITY - Ultrastar DC HC520 is designed for traditional storage and server applications as well as distributed and scalable computing, including block and file storage architectures. REBUILD ASSIST FEATURE - helps dramatically reduce RAID rebuild times and maintain system performance during the rebuild process.