I MANUFACTURE COPPER GASKETS FOR STOCK AND RACING APPLICATIONS. THIS GASKET IS CNC MACHINED FROM COPPER SHEET. PROBABLY THE LAST GASKET YOU WILL EVER NEED FOR YOUR ENGINE. COPPER CAN BE USED MULTIPLE TIMES IF NOT DAMAGED. PLEASE BE SURE GASKET WILL WORK FOR YOUR APPLICATION GASKETS MAY OR MAY NOT BE STOCK BORE OR THICKNESS. MADE IN USA