The Hydraulic Dry Bag from Sea To Summit is a super heavy duty dry bag made of 600D TPU laminated fabric with all-welded construction for waterproof durability. The fabric is PVC free and UV resistant. It sheds water and does not crack in extreme cold.The molded interlocking closure securely seals the bag. The dry bags have an oval base to resist rolling and take less room when stacked. Heavy duty Hypalon lash loops are RF welded at the sides and provide secure attachment or lashing points.