Safety Washer H can be used with high- tensile bolts. These are stronger safety disc washers having higher thickness for higher pre-tensioning loads. The outside and inside diameters as well as the serrations are same as GS series.Spring Steel according to DIN EN 10132-4, Corrosion-resistant Stainless Steel 1.4310, Inconel etc.Phosphated, Mechanical Zinc plated (Cr 6-free), Zinc Lamellar Coatings, Electrolytic Plating.