This is the Gasket Set for the OS Max .46 AX Engine, OSMG547. / / INCLUDES: One Head gasket - this very thin metal gasket seals the gap between / the cylinder head and the crankcase. / One Backplate gasket - very thin O-ring gasket. / / SPECS: Head Gasket: B.P.gasket: / I.D.:22.2 (0.874") 28.5mm (1.122") / O.D.:28.5 (1.124") 29.8mm (1.173") / Thickness: 0.1 (0.005") 1.0mm (0.039") / mcw 2/20/04 / ir/jxs