Ultralight backpacking is exploding in popularity — and rightfully so: Going light means going farther, faster, and more comfortably, but you’ll need the right pack to do it with. We’ve been testing ...

(no cotton in this layer) _____ 1 rain jacket or poncho: coated nylon or waterproof/breathable fabric like Gore-tex. Make sure it’s still waterproof—the waterproof coating on nylon rain jackets ...