1/4"-20 x 2-13/16" bi-metal screws with a 300 series stainless steel head and threads fused to hardened steel lead threads and self-drilling point. Stalgard GB coating provides a galvanic barrier. #5 self-drilling point can drill thicknesses up to .500". #2 phillips drive. <br /><br />Bi-Flex fasteners provide unmatched corrosion resistance and high performance in a wide range of demanding applications, including aluminum, and are virtually immune to delayed embrittlement failures.