arge Double Wall Cardboard Boxes 18"x18"x20". A very common size used in the removals industry (along with our most popular 24x18x18" size), and also throughout various industrial businesses. Easily hand carriable once full and easily fits through doorways. A solid large size it is also good for heavy items, files & folder storage, warehouse dispatches, and for use as postal boxes through courier networks. All dimensions stated are length x width x height.