These 3 1/2 Colorado are a premuim Blade. The Rainbow finish has a Polyurethane coating to stop any paint peeling. They start as Polish Brass material. There polished and plated, Copper, Silver, Gold and 50/50 Gold/Nickle. The Copper has a Polyurethane finish added to stop any tarnishing or finger prints. Your Gold and Silver finish have a much brighter flash than a Polish Brass or Nickle finish . for better fish attraction.