The Hurlcon heater 40mm union kit is available for the HX70, WX75, HX120, WX120, HX150, JX130, JX160 range of heaters. These 40mm union kits do not come with the 40mm tail, the oring and the union. The heater 40mm union kits are specifically for the Hurlcon and Astral Pool heaters and they are the water in/out connectors that connect the water pipes to the manifold. The 50mm union kit is designed for the MX range of heaters. Order your new Hurlcon heater union kit today.