Air filters from Green Label Parts are made with a unique foam pre-cleaner especially for use with Cummins Onan RV generators. The filter paper in air filters made by other manufacturers could have a lower density, and with time, the sealing surfaces might brittlely split, letting unclean air into the engine intake system. Piston rings and cylinders can be worn out with just a thimbleful of dirt over time. For precise maintenance schedules, please consult your operator's manual. Fits Onan Generator Models: KYD 50 HZ (Spec A-B), KYD 60 Hz (Spec A-B), KY 50 Hz (Spec B-H), KY 60 Hz (Spec B-H), KY 50 Hz (Spec J-N, P), KY 60 Hz (Spec J-N, P).