Heavy Duty Boxes are usually bigger in size and mostly one box is placed over one pallet. If the product to be packed weighs more than 500Kg then these sort of corrugated boxes are preferred. These boxes usually have flaps on the bottom side and a tray type cap on the other side. Paper quality with higher GSM and Bursting Factor and thickness ranging from 7ply to 11ply are used to withstand the product weight.