#9-15 metal to wood screws are sealing self-piercing tapping screws made from heat treated C1022 steel, case hardened for roofing and siding applications. A 1/4" across flats high hat hex washer head with assembled EPDM washer offers easy driving and conforms to the metal surface for a secure and long-lasting seal. The twin lead type 17 point and hi-lo threads offer faster drive time and greater resistance to pullout. 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 and distinctive yellow color for better retail identity.