Easy to Install: The Heater Split Nut mounts to the heater tube using for 2 screws to hold it in place and screws onto the heater threaded union with a gasket between the union and tube. Number of Pieces:for 2 x for 2" Heater Split Nuts, 4 Screws and for 2 Gaskets for use with a for 2" Heater Tube & Union.