Aprilaire 4181 Scale Control Insert for Humidifier Models 350, 360
The Aprilaire 4181 Scale Control Insert is the u-shaped component which encases the Water Panel. Their purpose is to direct any mineral which builds up back into the evaporative panel. Used with the water panel number 35 and the water distribution tray number 4182. Also see part number 4785, maintenance kit for the Models 350 and 360.