MADE IN USA BORE SIZE 51.61MM THICKNESS YOU CHOOSE .016 .021 .026 .032 .042  I MANUFACTURE COPPER GASKETS FOR STOCK AND RACING APPLICATIONS. THIS GASKET IS CNC MACHINED FROM  PERCENT COPPER SHEET. PROBABLY THE LAST GASKET YOU WILL EVER NEED FOR YOUR ENGINE. COPPER CAN BE USED MULTIPLE TIMES IF NOT DAMAGED.