Seagate ST3500642U2-RK 500 GB External Hard Drive USB 2.0 Push button operation and BounceBack Express software makes it fast and easy to back up data High-performance 7200 RPM drive with 16 MB cache and USB 2.0 interface On/off button eliminates concerns that your hard drive hasn't been shut down safely Built-in self-monitoring technology continuously checks your hard drive for data safety and drive performance Hot-swappable, so you can connect and disconnect without turning off your computer