Mil Spec Boxes are made with wet strength corrugated fiberboard. These boxes are manufactured with ASTM-D4727 spec board and fabricated to ASTM-D5118 specifications. V3C boxes have a burst strength of 350# to 400# and meet many military packaging specifications. A limited supply of common sizes are in stock in both V3C and W5C grades. Fabrication of custom sizes require a lead time of 14 to 21 days and can be ordered to size. Water resistant boxes meet the specifications noted above.