18 x 6 x 45" Side Loading Boxes. These cartons open along the ends for easy insertion of frames, mirrors and other flat products. Designed with full overlap (FOL) flaps for added protection. Boxes are manufactured from 275#/ECT-44 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.