This product is discontinued and has been replaced by 434882. The Worcester Bosch ignition device kit is designed to be installed near the electrode of a Worcester Bosch boiler. The electrode generates a spark that ignites the boiler's fuel. An ignition electrode generates the spark that starts combustion within the burner, whereas flame-sensing electrodes check to see if there is a flame present in the burner to ensure that the boiler does not continue to supply gas without a flame.