Two layer YKK zippers with center flap for an anti-leak style. Our zipper program presents double protection and minimizes worry around the zipper method to offer a few years of use. I've my package and am shortly about to develop it. I checked out the Sealine S23 I have and https://oxygen-chamber-cost07384.blogrelation.com/42145446/what-does-how-much-is-a-hyperbaric-oxygen-chamber-cost-mean