A tapping screw with an integrally formed hex washer head and assembled with 9/16 (5/8 for #14) outside diameter bonded NEO-EPDM washer to create a leak proof seal, spaced or unified threads, and a #2 or #3 drill point. Designed to drill through steel. AISI 1022 or equivalent steel. Rockwell C50-56. Meets F.I.P.-1000.7 for torsional strength & drill speed. Meets ASTM A 510 for carbon steel manufacturing. Zinc plating meets ASTM B-117 for salt spray corrosion. Manufactured to SAE J78 for dimensional specifications.Intercorp