HGST Travelstar 5K1000 HTS541064A9E680 - hard drive - 640 GB - SATA 6Gb/s

Travelstar 5K1000 is a 5400 RPM, 500GB/platter, 2.5-inch hard drive. This standard 9.5mm, two-disk design, intended for use in notebook PCs, external storage, gaming consoles and other mobile applications, leverages advanced format, which increases the physical sector size on hard drives from 512 bytes to 4096 (4K) bytes to increase drive capacities and improve error correction capabilities.