This is the exhaust adapter for the O.S. #855 muffler FEATURES: Natural aluminum construction INCLUDES: One Exhaust Extension Adapter for #855 Muffler One 3.5x12mm allen head screw Two 4x15mm allen head screws REQUIRES: 3mm hex wrench 4x18mm screws OSMG6931 to attach adapter to muffler SPECS: Thickness: 9.4mm (3/8") COMMENTS: This allows you to extend your muffler 3/8" away from the engine. It bolts on directly to the engine with the two included 4x15mm screws and the one 3.5x12mm screw then the muffler bolts to this adapter with two 4x18mm screws tjt 042205 ir/jl