20 [EN] EN 14399-10 (HR) - 2018 High-Strength Structural Bolting Assemblies for Preloading - System HRC - Regular Nuts (HR) 21 [DIN] DIN 2510-5 (NF / TF) - 1971 Bolted Connections with Reduced Shank Hexagon Nuts 22 [DIN] DIN 6195 Steel Hex Nuts with Large Width Across Flats fo...