What is the application of waterproof zipper on waterproof waist bag?

In fact, it is not surprising that waterproof pockets, swimming pockets, can soak in water and stay in the water for a long time. This most critical component is the airtight zipper. The airtight zipper was originally a supporting product for space protective suits. It was originally developed by NASA to make high-altitude pressurized suits, and later used to make space suits, which can keep space suits in the vacuum of space air pressure inside. The airtight zipper is a kind of zipper with relatively high requirements on waterproofing among waterproof zippers, and is generally defined as a zipper with ipx8 waterproof performance.