10-16 x 1 1/4 Hex Washer Head Self Drill Screw w/ Neo 410 SS . 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. 410 Stainless steel to drill through harder material and provide the corrosion resistance. Rockwell C50-56. Meets F.I.P.-1000.7 for torsional strength & drill speed.  Meets F.I.P.-1000.7 for torsional strength & drill speed.  Manufactured to SAE J78 for dimensional specifications