LOKSAK Element waterproof bags are made using a next generation 6 mil film with 4 times less stretch, a much firmer hold, and twice the tear and puncture resistance of conventionally produced polyethylene bag. The LOKSAK is on par with PVC material of the same thickness in terms of durability, but has a lower cold-crack tolerance (minus 40 F) than that of PVC / Vinyl (0 degrees F). The LOKSAK has been certified by the U.S. Navy (NEDU) to keep water out to depths up to 200 feet.