No zips means no leakage, so this large waterproof rucksack has a seamless electronically-welded construction and a simple to use two-way sealing system, making it fully submersible.From the large front mesh zip pocket to the padded shoulder straps and air-flow back panel, this feature-packed Overboard Waterproof Backpack is a comfortable and handy bit of kit for any water-based sportsman.