The seal line bulkhead view 20l dry bag the waterproof bulkhead view dry bag is designed to efficiently stow in boat hatches and cramped compartments while the integrated window makes it easy to identify contents and the discreet purgeairtrade valve vents any trapped air helping optimize space usage seal line bulkhead view 20l dry bag features purgeairtrade equipped new waterproof valve helps the bag compress further once itrsquos been sealed see inside