These mailers are constructed from strong cardboard made with 200#/32ECT material. This construction gives the boxes great stacking strength, and this is why we provide these mailers in flat bales. These boxes come in a pre-cut arrangement that promotes quick assembly and use of these boxes. Due to oyster white color of the outer surface on these boxes, you can easily mention product name and shipping information. These corrugated mailers are most suitable for storing and shipping books, catalogs, picture frames, magazines, letterhead and many such things. Delivered in bulk quantities, these boxes are cost-effective.