Mr. Gasket 7151MRG Copper Seal Medium Race Square Port Exhaust Gasket Race-track proven to eliminate gasket leaks Medium race square port dimentions are 1.45 wide x 1.48 height Long-lasting solid copper will not shrink, deteriorate or blow out Forms a leakproof seal even on slightly irregular or damaged surfaces O-ring design increases sealing pressure to create a tight, leak-proof seal