Dimensions: 41.00mm/1.614" OD; 31.00mm/1.220" ID; 11.00mm/0.434" height. U.S.A. made cast iron valve seats from Kibblewhite Precision Machining for leaded and unleaded fuels including methanol and ethanol blends. Ssuitable for both intake as exhaust. Offers excellent thermal characteristics and resists micro-welding. With leading edge to ease installation. Note: Abbreviations used OD = Outside Diameter, ID = Inside Diameter.