... of the product: all sizesurface of the product: yellow zinc plated , zinc plated , black , plain , H.G.Dpacking of the product: bulk ... materials. For finishing, we provide black oxide, zinc electroplating, phosphate, copper plating, mechanical galvanization, hot dip galvanization, and Dacromet. Our products ... about our company, you are welcomed to visit us. hexagon bolt DIN933 yellow zinc plated