These sheet-steel containers had completely replaced the wooden boxes formerly used for small arms ammunition. They were fire-resistant, virtually moisture-proof, and since no wood was used in their construction they would never have been attacked by termites, a constant menace to wooden boxes in storage. Low manufacturing cost permitted them being classified as expendable items yet if transportation to supply centers was available they had to be refilled over and over again. The hinged lids sealed tightly but could be completely removed if necessary, hasps permit the boxes to be hung on the brackets of .30 calibre and .50 calibre machine gun mounts, the carrying handles folded into recesses flush with the lids and the boxes could be packed solidly one on top of another.