PurgeAir™-equipped: Our unique and waterproof PurgeAir valve vents trapped air, helping the dry bag compress further after being sealed, and is both more durable and more reliably waterproof than waterproof/breathable fabric membranes.See inside: Waterproof translucent materials allow contents to be easily identified without having to open the bag, simplifying packing and finding what you're looking for. Color-coded oval bottom: Color-coding distinguishes between bags; stable shape won't easily roll around and is easy to store, stack, and pack. Durably constructed: Fully welded seams result in stronger and more durably waterproof construction compared to sewn-and-taped seams. Tight, simple sealing: Updated DrySeal™ roll-top closure makes it easier and more intuitive to achieve an optimal seal. PVC-Free: Materials have a reduced environmental impact over vinyl-coated materials.