Spax Cross Recess Washer Head fasteners with zinc coating are designed for use in multiple material connections often found inside residential buildings. Most of these screws are used to attach thin wood panels or backing materials to wood or MDF substrates where countersinking the head is not wanted. The wide heads utilize a large bearing surface which allows for a firm hold on the attachment piece and reduces over-penetration of the head into the wood substrate. Cold-rolled "carbon steel" wire, heat treated to grade 5 durability and plated with a zinc finish to prevent red rust. "Clear zinc" is tested and recognized for use in above ground contact pressure treated lumber for interior dry/damp general construction applications.