Hex bolt Pro Bolt Race Spec screws allow the use of safety wire through the additional holes in the head of the screw. Made of 316 stainless steel, which offers the following benefits: - excellent strength - excellent corrosion resistance - high resistance to acids The offered stainless steel screws are all polished to a high gloss. Stainless steels are iron alloys with a minimum of 10.5% chromium added to other elements (nickel, molybdenum, titanium, copper, carbon, nitrogen) to increase properties such as formability and strength. A chromium-rich oxide layer gives stainless steel its corrosion resistance.