8 TBytes Western Digital™ Purple HDD. Size: 3.5'' (Width: 102mm x Height: 26mm x Depth / length: 147mm). 256 MB cache. 5,400 rpm. Read: 245 MB/s. SATA/600 interface. Power: 15-pin connector. 24/7 continuous operation (MTBF: 1,000,000 hours).