GRK’s PHEINOX Trim Head screws have the smallest screw head available preventing most material from splitting. Pre-drilling is only necessary if the building material’s limitations require a pilot hole to be drilled (ie. Hardwoods like Mahogany). PHEINOX stainless steel screws are made from only the best grade of stainless steel wire, 305. Use PHEINOX screws for GRK for projects that should last a lifetime.