The g drive mobile usb hard drive from g technology is a stylish thin aluminium portable storage device that combines usb 30 high performance with up to 3tb of storage easy to set up and compatible with time machine youll find it perfect for storing your most important documents digital video photo and music files the g drive mobile usb features a drive speed of 5400rpm and is bus powered so when youre out and about you dont need to add an external ac power supply to your laptop case