DUB-699 Muffler Extension .40-.46 PDF Print $6.93 SKU: DUB-699 DUB-699 Muffler Extension .40-.46 Add to Wishlist Add to Compare Back to: Exhaust Systems Description This is a 1/2" muffler extension for .40-.46 size engines such as O.S. MAX, ASP, Magnum and Thunder Tiger. This goes between the engine and muffler, bringing the muffler outside the fuselage.