Kraft Corrugated Mailers are lightweight to save on postage. Perfect for shipping small, fragile items such as tools, glassware or products. Manufactured from ECT-32-B, kraft corrugated. Crush resistant mailers fold to provide double walls of protection on front and sides. These one-piece mailers fold together in seconds. No tape, glue or staples are needed. All sizes ship and store flat to save space.