Kohler Vertical-Mount Engine Muffler- Oil Filter Side Discharge Confidant EngineThis Kohler Vertical-Mount Engine Muffler helps you reduce mower noise. The muffler and manifold system is designed for use with 21HP Kohler Confidant oil filter side discharge engines. HP 21, Application Sidemount, Engine Type Kohler, Sides Oil filter. Vertical-mount design for use with select 21HP.