Mitsubishi Aircon Catechin Air Filter Plasma Deodorizing Filter (Left) MSZ-FB25VA-A1 MSZ-FB35VA-A1 MSZ-FB50VA-A1Mitsubishi Aircon Catechin Air Filter Plasma Deodorizing Filter (Left) MSZ FB25VA A1 MSZ FB35VA A1 MSZ FB50VA A1 Plasma Deodorizing Filter. We recommend cleaning your filter every 3 months, and for best performance replace it every 12 months. The model number of your Mitsubishi heatpump is on a label on the bottom of the indoor unit. For use in the following Heat Pump Models: MSZ FB25VA A1 MSZ FB35VA A1 MSZ FB50VA A1 MAC 307FT