Original Link: http://store.apple.com/us/product/MD464

The Apple Store:

Easily connect your Thunderbolt-equipped Mac to a FireWire device with the Apple Thunderbolt to FireWire Adapter. Small and compact, it connects to the Thunderbolt port on your Mac computer, giving you a FireWire 800 port that supplies up to 7W for bus-powered peripherals like hard drives and audio devices.

Handy for using my FireWire drive on my Air..