This is the Gasket Set for the O.S. Max .50SX-H Helicopter Engine. This set contains the backplate and the cylinder head gasket. FEATURES: Replaces worn or missing backplate and cylinder head gaskets. Backplate gasket is made of thin paper composite, cylinder head gasket is brass. INCLUDES: One Gasket Set for the OS .50SX-H Helicopter Engine #15500 (OSMG1950 REQUIRES: Removal of the cylinder head and the backplate. JXS 4/10/01 ir/jl