Buffalo Replacement 500GB Drive for DriveStation Duo 1.0TB. Hard drive capacity: 500 GB, Hard drive size: 88.9 mm (3.5 "), Hard drive rotational speed: 7200 RPM. Height: 27 mm, Width: 102 mm, Depth: 147 mm. Operating temperature range (T-T): 5 - 35 °C, Operating relative humidity range: 20 - 80 %