Metal to metal screws are sealing self-drilling tapping screws made from C1022 steel, case hardened for roofing and siding applications. The screw drills its own hole, forms mating threads and makes a complete secure fastening in a single operation. Acorn International metal to metal screws have a #3 drill point for fastening sheets to purlins up to 1/4" total thickness with no predrilling. #12-14 screws are 5/16" across flats hex washer head and #14-14 screws are 3/8" across flats hex washer head with assembled EPDM washer for easy driving and conformance to the metal surface for a secure and long-lasting seal. All screws are 1,000 hour salt spray test dacro coated. Colored screws are powder coated over the dacro base coating. All Acorn International screws are packed 250 pieces in a heavy duty tear-off resealable bag, UPC coded and retail ready. All bag and carton labels are trilingual. Cartons are heavy duty cardboard of uniform size.