A-B1AF233-AI Pre-Filter, Kohler 20 08 3045One New Aftermarket Replacement Pre Filter for Kohler Courage Single Cylinder Engines This foam pre filter (pre cleaner) wraps around the primary air filter element to provide a first stage of filtration, capturing larger dust and debris particles before they reach the main air filter. Replacing the pre filter on a regular maintenance schedule extends the life of the primary air filter and helps protect Kohler Courage single cylinder engines from