Mirror moving boxes, 4-piece box, 30" x 40" x 3 1/2" 1 piece of 30" x 40", Kraft, 4/bundle. Four pieces are required to create a complete carton. Panels feature fragile, handle with care and do not lay flat messages. Manufactured from 200#/ect-32 Kraft corrugated. Shipped flat to save on storage space and shipping.