The air filter prevents the carburetor from taking in particles of dirt which can cause damage to the carburetor and the engine and impact negatively on performance. It should be cleaned frequently and replaced in the event of servicing. PIAGGIO can also supply air filters for the SHBC 19.19 (PV/ET3) and SHBC 18.16 (Ape50). The Ape air filter can also be fitted to the SHBC 19.19 Vespa carburetor with long stud bolts. As the original air filters are no longer available for the 16mm carburetors, we have reissued these as a SIP spare part.