Espar Glow Plug Screen aids in atomizing the fuel for a proper burn. A dirty or plugged glow pin screen can contribute to no starts, smoking and or low heat output. Included in this purchase is: one Glow Pin Screen and Insertion Tool. The Insertion Tool is required to properly install the Glow Pin Screen once the old screen is removed. For use with any 12 or 24 volt D2, D4 and B4 Airtronic heaters, also for any 12 or 24 volt D8W, D10W, and D12W M-II Hydronic heater.