Metal-to-metal screws are sealing self-drilling tapping screws made from 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 in total thickness with no predrilling. #12-14 screws are 5/16 in across flats hex washer head and #14-14 screws are 3/8 in 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 1000 hr 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 and distinctive yellow color for better retail identity.