Sealing Washer Finish Plain Metal Material Copper Material Grade/Class Not Graded For Screw Size M15 Inside Diameter 15 mm Outside Diameter 20 mm Maximum Thickness 1.5 mm Seal Material Copper System of Measurement Metric Pack Size Small Pack Heat Treatment Annealed Minimum Thickness 1.5 mm Thickness Tolerance +/-0.20 mm Package Quantity 50