Buffalo Replacement 500GB Drive for DriveStation Duo 1.0TB, 500 GB, 7200 RPM, 8 MB, 3.5", Serial ATA Buffalo Replacement 500GB Drive for DriveStation Duo 1.0TB. HDD capacity: 500 GB, HDD speed: 7200 RPM, Storage drive buffer size: 8 MB, HDD size: 3.5", Interface: Serial ATA