M16 Countersunk Head Blind Rivet Nut - Zinc Plated Mild Steel The countersunk head style provides a stronger head and will install flush in a countersunk hole Grip Range: 2.0-4.5 mm Hole Diameter +0.1 / -0.0: 17 mm Body Diameter: 19.9 mm Head Diameter: 26 mm Head Thickness: 4 mm Overall Length: 33 mm Material Finish Zinc Plated Mild Steel