49 CFR § 178.515 - Standards for reconstituted wood boxes.
(a) The identification code for a reconstituted wood box is 4F.
(b) Construction requirements for reconstituted wood boxes are as follows:
(1) The walls of boxes must be made of water-resistant, reconstituted wood such as hardboard, particle board, or other suitable type. The strength of the material used and the method of construction must be appropriate to the capacity of the boxes and their intended use.
(2) Other parts of the box may be made of other suitable materials.
(3) Boxes must be securely assembled by means of suitable devices.
(4) Maximum net mass: 400 kg (882 pounds).