Finerfilters FF-FC04 water filter cartridge compatible with Lincat FC04 boiler water filter. The cartridge has a 1 Micron rating, meaning it will remove Class 1 particulates from the water. This filter is compatible with the LINCAT FilterFlow FX Series of Boilers Including; EB3FX, EB3FX/PB, EB3FX/TT, EB4FX, EB6FX, EB6TFX