RoHS or Restriction of Hazardous Substances Directive is a directive adopted by the European Union in 2003. It set guidelines to help restrict the use of six hazardous materials in the manufacturing process of different types of electronics. The six hazardous materials are: Lead (Pb), Mercury (Hg), Cadmium (Cd), Hexavalent chromium (Cr6+), Polybrominated biphenyls (PBB), Polybrominated diphenyl ether (PBDE). Click here for more info.