This hex nut is manufactured to ISO 4032 standards and made from 25CrMo4+QT steel (1.7218) with a plain finish—meaning no coating or surface treatment has been applied. While the material is strong, it offers little inherent resistance to corrosion. The nut features metric threading and is designed for use in pressure vessel applications. It's approved for use under the Pressure Equipment Directive (PED). An EN 10204 3.1 certificate is available upon request for an additional fee.