S&S air horns are fully machined from light weight alloy aluminum castings.  This air horn can also be used with any stock carburetor with an identical air cleaner/air horn mounting pattern.  These include Tillotson, Bendix or butterfly type Keihin.  Each air horn comes with three mounting screws.  2.5" in length. 

Notes: S&S recommends that air horns be used in racing applications only as they do not provide the filtration required to protect the engine on a day to day basis.  Any installation of an air horn on an S&S carb in place of an air cleaner requires an S&S carb support bracket, 16-0471, to securely fasten the carb to the engine.  This bracket is included in the air horn conversion kits.  S&S recommends that bowl vent plug in bottom of carb body be removed when air horn is installed, as air horn may obstruct bowl vent in air cleaner mounting surface of carb body.  S&S Part #: 17-0042

*Special Thanks To Doghouse Dave For Providing Additional Photos.