This is the 12F2 (B) Carburetor for the OS Engines 12XZ Speed Spec III Engine, OSMG1992. FEATURES: Fully assembled and ready to install INCLUDES: Carburetor, key #8 Thermo Insulator, key #10 Rubber Gasket, key #11 Red Aluminum Reducer jxs 02/05/13 ir/jxs