20 x 20 x 4' Flat Corrugated Boxes. The smaller depths on these cartons provide an ideal fit for shallow products. Perfect for shipping apparel, books, picture frames, artwork, mirrors and clothing. Boxes are manufactured from 200#/ECT-32 kraft corrugated. Corrugated boxes are reusable and recyclable. Cartons are sold in bundle quantities and ship flat to save on storage space and shipping. Proudly made in the USA!