M8 Knurled body countersunk head blind rivet nut - T304 (A2) Stainless Steel The countersunk head style provides a stronger head and will install flush in a countersunk hole Grip Range: 1.5-4.0 mm Hole Diameter +0.1 / -0.0: 11 mm Body Diameter: 10.9 mm Head Diameter: 13.5 mm Head Thickness: 1.5 mm Overall Length: 18 mm Material Finish T304 Stainless steel provides a corrosion and oxidation resistance, however it can tarnish. Used extensively in every day life, but if you need a higher level of corrosion resistance such as in a marine environment look for T316