Abstract: A heavy duty box and blank for forming the box includes structure to increase the strength of the corner regions of the box so that they may provide direct and additional support for the downwardly depending skirt of the cover for the box. The box includes, at each corner, an outwardly projecting tab which is located to provide additional support for the lower edge of the corner region of the skirt of the cover. The invention avoids the necessity of using a cover having a full length skirt and results in a box which better withstands vertical loads, as when other boxes are stacked on top of it.