I have bought several similar
I have bought several similar cases of other brands but I've returned most of them due to quality problems. I've never had a problem with Pelican cases. Their "o" ring is tight in place, tabs closed with even pressure which protects the O ring. The type of material (5 PP) is very adequate for storing paper or books that require an acid-free container (Great for antique book preservation) (The pressure valve is a most for this purpose)