| Aprilaire 112, 224 Humidifier Part Red Orifice 4021, 2 Pack Even the smallest pieces are crucial to making sure your furnace mount humidifier works properly. This replacement red orifice is made to fit Aprilaire humidifer models 112 and 224. Humidifier orificis should be replaced annually For optimium perFormance and to stop the build-up of minerals and grit. For use with a variety of Aprilaire models listed below. Aprilaire is also known as Aprilair, April Aire, and April Air. Aprilaire's company mission is to provide superior indoor air quality products For new and existing homes and businesses. Includes 2 red orifices, part number 0421. Fits Aprilaire Models: 112 and 224 | 
