Hayward FDXLFHA1930 H-Series FD Heater Header Assembly. Hayward part number FDXLFHA1930. For Universal H-Series Low Nox Heaters. Only works with specific models listed below. Fits Hayward H150FDN, H150FDP. Fits Hayward H200FDN, H200FDP. Fits Hayward H250FDN, H250FDP. Fits Hayward H300FDN, H300FDP. Fits Hayward H350FDN, H350FDP. Fits Hayward H400FDN, H400FDP.