Western Digital has announced that it will be selling the world's first 4TB external hard drive. However, the My Book Studio Edition II dual-drive storage system seems to be designed for Macs, not PCs.

Two RAID 0 striped disks combine to provide a high-speed interface for digital content. There are four options for connection - eSATA, Firewire 400, Firewire 800 and USB 2.0.

There's also Western Digital's "GreenPower" tech that ensures that the device doesn't drink up power like a thirsty cowboy entering a saloon after three weeks in the hills. It keeps it quiet, too.

A capacity gauge shows how much space is left at a glance, and the drive is user-servicable, so when we're all downloading 20TB files fifty times a day, you can swap out the drive and it'll still be useful.

The My Book Studio Edition II costs £600, comes formatted for Macs, not PCs, and is available now.