This is the replacement Dummy Exhaust Manifold Set (exhaust stacks) for the Top Flite P-51D Mustang ARF (TOPA0950). FEATURES: Plastic construction INCLUDES: Two dummy exhaust manifolds (stacks) (key #20 & 24) SPECS: Length: 6.75" (171mm) REQUIRES: Installation following the model manual tlw 3/6/08 ir/jxs