27" x 27" x 27" - Corrugated boxes are manufactured from strong ECT-32 kraft corrugated and are 100% recyclable. Boxes are sold in bundle or bale quantities. All cartons ship and store flat to save space. Popular for their strength, durability, lightness, recyclability, and cost-effectiveness, corrugated boxes are used for the shipping of a variety of items. ECT is a measure of the edgewise compressive strength of corrugated board. It is measured by compressing a small segment of board on edge between two rigid plates perpendicular to the direction of the flutes until a peak load is established.