Fastener Seal - Zinc-Plated Steel with Buna-N Rubber Sealing Washer Type Metal Bonded Washer Finish Zinc Plated Metal Material Steel Material Grade/Class Not Graded For Screw Size 1 in Inside Diameter 1.02 in Outside Diameter 1.75 in Maximum Thickness 0.223 in Seal Material Buna-N System of Measurement Inch Pack Size Small Pack