The Twinn Tarp is an ultralight sleep-shelter with enough room for two. Designed for those travelling light, it packs down smaller than a Nalgene bottle and weighs just 275g, while still offering plenty of protection from the elements. Just prop it up with a pair of trekking poles, peg down those guylines and you're set. It's no Winnebago, but for keeping the weight down during multi-day treks it's a really useful piece of kit.