Western Digital Green 4TB. Hard drive capacity: 4000 GB, Hard drive interface: Serial ATA III, Hard drive speed: Variable. Power consumption (standby): 0.40 W, Power consumption (read): 4.50 W, Power consumption (write): 4.50 W. Width: 4" (101.6 mm), Height: 1.03" (26.1 mm), Depth: 5.79" (147 mm). Color of product: Black, Data transfer rate: 6 Gbit/s, Connectivity technology: Wired