The Evolution SuperTEK7 Hex Head Composite Panel Fastener, with a 16mm Washer, is designed for fixing steel to steel. Made from carbon steel and AISI C1022 material grade, with a 1000hr Evoshield coating. Single thread form ('V' fluted), drilling capacity of 3.5-18.5mm and a recommended drill speed of 1500-2500 RPM.