These principles include requiring suppliers who manufacture components, parts, or products containing tin, tantalum, tungsten, and/or gold to commit to sourcing those materials from environmentally and socially responsible sources only, and in compliance with SEC ruling and OECD guidance. Section gold, tin, tungsten, and tantalum make efforts to determine if those materials came from the Democratic Republic of Congo (DRC) or an adjoining country and, if so, to carry out a “due diligence” review of their supply chain to determine whether their mineral purchases are funding armed groups in eastern DRC.