These Forgefix Plasterboard nails are Zinc Yellow Passivated for corrosion resistance. They have indented shanks and countersunk heads, and can be used widely in many joinery applications. APPLICATION:The shape of the nail makes them ideal for fixing plasterboard and cladding. The Zinc Yellow Passivation process of electroplating is similar to the Galvanised and Zinc Plated processes but with the addition of a yellow dye. It provides a coating that is aesthetically pleasing, and which offers excellent resistance to corrosion. Countersunk heads are designed to fit flush with substrates to leave a smooth surface finish. The twin thread's main function is to enable an easy start when driving.