These "Crush Proof" white Corrugated Mailing Boxes are constructed to create a professional appearance for shipment of catalogs, literature mailers, machined parts, pictures, printed material, etc. Made from 200# (32 ECT) test oyster white corrugated on the outside and natural brown kraft on the inside. Choose from multiple designs. Most styles fold together in seconds without tape, glue, staples or hot melt. All Bubble and Corrugated Mailers ship flat to save on cost and space. All styles are appoved for shipment of your product using Post Office (USPS), UPS, FedEx, and many other carriers. Sizes shown in the item description are the inside dimensions of the box (in inches) and are in the following order: Length, Width and Height.