25L dry bag and sleeping pad inflator in one. made from 75D ripstop polyester with TPU reflective coated fabric. the purge valve near the bottom of the bag will fit over your sleeping mat valve and with several pumping actions you can inflate your pad to the desired firmness. The bag itself can be used to store your gear and offer water resistant protection. ( due to the valve is is slightly less waterproof than a traditional style dry bag.