Aprilaire #4007 White Orifice

Aprilaire Humidifier White Orifice - Part #4007 Replacement Orifice for Aprilaire Models 110 and 220 Humidifiers This simple but critical part regulates the flow of water into the humidifier. Over time it can become clogged with sediments or mineral deposits. It should be replaced annually for optimum performance. Be sure to clean or replace your In Line Strainer when you replace the orifice.