Internal fuel metering pump filter

Internal fuel metering pump filter. To replace this filter, you need to unscrew intake spigot on the fuel pump. Heatso recommends replacing internal fuel filter at least once a year. Fits majority of Fuel pumps for Airtronic and Hydronic heaters. This is a must have service part for Airtronic D2 , D4, B4 , D2L, D4R, D4L, B4L.