Perfect for that unforseen canyon rappel, or for Tarzan'ing across a battle station's inexplicably dangerous chasm with your princess. After you use it, you can send it back to the folks at Survival Straps and they will re-wind it for you, free of charge.

And for even more thrift, Instructables user Stormdrane has a great guide for weaving up your own. The pre-wound version from Survival Straps will run you $18-$22 depending on the buckle you want, and are available in 30 colors. [Survival Straps via Boing Boing Gadgets, Instructables]