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 0.988 in Outside Diameter 1.76 in Maximum Thickness 0.087 in Seal Material Buna-N System of Measurement Inch Pack Size Small Pack