Western Digital My Book Premium 500GB USB/FW 400 Ext Hard Drive Western Digital My Book Premium Edition 500 GB USB/Firewire Ext HDD General Features: Capacity: 500 GB Elegant, small footprint design Interface: USB 2.0 and FireWire 400 Rotational Speed: 7200 RPM Read Seek Time: 8.9 ms (average) Average Latency: 4.20 ms Automatic power-up Safe Shutdown LED activity lights Convection cooling system Thermostatically controlled fan keep