are super strong yet light-weight to save on postage. Perfect for shipping small, light-weight fragile items. Corrugated Mailers are manufactured from 200#/ECT-32B oyster white corrugated. Crush resistant mailer folds to provide double walls of protection on front and sides. Unique "Wave-Rule" edge virtually eliminates paper cuts. These one piece mailers fold together in seconds. No tape, glue or staples needed. All ship and store flat to save space.