Samsung S2 Portable 640 GB, S Series. Hard drive capacity: 640 GB, Hard drive interface: USB 2.0, Hard drive size: 63.5 mm (2.5 "). Weight: 170 g, Width: 82 mm, Depth: 111 mm. Operating temperature range (T-T): 5 - 40 °C, Storage temperature range (T-T): -20 - 65 °C. Data transfer rate (max): 480 Mbit/s