BAJA CYL GASKET .040 COPPERReuseable copper cylinder gasket. Fits Zenoah G230RC / G260RC engines. Also fits Chung Yang CY23RC / CY26RC / CY27RC / CY29RC / GP290 engines. Copper gasket is .040" (1mm) thick, double the thickness of a stock gasket. By installing this gasket, you will increase your squish clearance, allowing installation of stroker crankshafts for increased engine displacement. This stronger gasket resists leaking and blowout.