The Evolution Zinc Coated Tek 3 Hex Head Screw, with a 19mm Bonded EPDM Washer, is designed for fastening where a high end corrosion resistant coating is not required. Made from carbon steel and AISI C1022 material grade, with a Zinc coating and an effective thread length of 90.0mm. Twin, coarse thread form, a drilling capacity of 1.2-3.5mm and a recommended drill speed of 1500-2500 RPM.