While steel drums may look alike, once they are United Nations certified for hazardous materials, they are as unique as each manufacturer. The entire design of a UN drum, and all its components (metal thickness of the body and heads, ring type, gasket, bolt, nut, plugs), is defined when being subjected to the Performance Oriented Packaging Standards per CFR 178.600, the US Code of Federal Regulations. The specific components used to perform the test comprise a drum type, or certification, that must meet a designated test standard for classified HazMat products. Once in the field, shippers cannot alter or interchange any of these components, even though they may appear similar, as it will impact the ability of the drum to perform as certified. This also applies to the required Closure Instructions per CFR 178.2(c), which are required to be given to the shipper by the packaging manufacturer. If replacement parts are needed, fillers must make sure that they get the originally tested components from the manufacturer. Once a drum enters transportation, compliance with the UN Certification is the responsibility of the shipper.