These Forgefix Mirror Screws are zinc plated for resistance to corrosion, and have a slotted screw head and a threaded female insert in the head and shank. They have a chrome plated dome with a threaded machine screw type male insert, and screw-in top.Often used when fixing mirrors or signage, the single threaded screws will hold firm in wall plugs. APPLICATION:Suitable for use when fixing mirrors or signage in sanitary and similar locations. 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 substrates 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. With Slotted screwdrivers it is importa