Western Digital™ Purple 2TB HDD. Size: 3.5'' (Width: 101.6mm x Height: 26.1mm x Depth/Length: 147mm). 256MB cache. 5,400 rpm. Read: 175MB/s. SATA/600 interface. Power: 15-pin connector. 24/7 continuous operation (MTBF: 1,000,000 hours).