The Simpson Strong-Tie® Fascia-Fastening Solution™ consists of the counterbore bit and fascia screw, and is specially designed to securely fasten composite and PVC fascia while providing superior corrosion resistance. The counterbore bit is specially designed to bore a hole that, when the fascia screw is installed, allows the material to expand and contract as the enviroment changes. The result is a clean, professional installation that prevents occurances of head pullover, broken screws, warping, buckling and oil-canning. • Use of the fascia counterbore bit is crucial to proper installation of the fascia board • The fascia counterbore bit bores a hole through the fascia material that is wider than the shank of the fascia screw • The bit countersinks so the head of the screw is flush with the material surface