Samsung M2 Portable 640GB. Hard drive capacity: 640 GB, Hard drive interface: USB 3.0, Hard drive size: 63.5 mm (2.5 "). Data transfer rate: 5000 Mbit/s. Colour of product: Grey. Weight: 155 g, Width: 81.9 mm, Depth: 110.6 mm. Operating temperature range (T-T): 5 - 40 °C, Storage temperature range (T-T): -20 - 65 °C