●Fitment: Exhaust gaskets are compatible with Honda CB 650F, 650FA. ●Inner diameter: 35 mm/1.37 inches. Outer diameter: 43 mm/1.69 inches. Thickness: 4 mm/0.15 inches. ●Material: Copper plated surface, heat resistant and durable, provides good anti-shock effect. ●Function: This gasket fits between the exhaust manifold and the cylinder head. Reduce noise and make your motorcycle more stable and comfortable. ●Note: If the gasket is too loose, you can apply some butter or sealant to the gasket to stick it, then install the exhaust pipe.