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 1/2 in Inside Diameter 0.51 in Outside Diameter 1 in Maximum Thickness 0.157 in Seal Material Buna-N System of Measurement Inch Pack Size Small Pack Package Quantity 5