These Forgefix Screw Hooks are zinc plated for increased resistance to corrosion. They simply screw directly into timber and similar materials. Drilling a pilot hole is advisable. The screw head is also suitable for use with all types of wall plugs. APPLICATION: Screw Hooks are used to attach cables, wires and twine to many numerous applications. Also ideal as a storage accessory for use as a hanging hook. Zinc coatings prevent oxidation of the protected metal to create a longer lasting finish. It does this by forming a barrier and by acting as a sacrificial anode if this barrier is damaged. Zinc oxide is a fine white dust that (in contrast to iron oxide) does not trigger a breakdown of the substrate’s surface integrity as it is formed. The zinc oxide, if left intact, can act as a barrier to further oxidation, in a way similar to the protection afforded to aluminum and stainless steels by their oxide layers.