These cartons open along the ends for easy insertion of frames, mirrors and other flat products Designed with full overlap (F.O.L.) flaps for added protection. Manufactured from 275#/ECT-44 kraft corrugated. Boxes are sold in bundle quantities and ship flat to save on storage space and shipping. Office Depot Brand Side Loading Boxes 18in. x 6in. x 45in., Bundle of 5 is one of many Shipping Boxes available through Office Depot. Made by Office Depot.