This is one of the most popular split nut unions, it is made to replace heater flange nuts. It has a large flange for stainless steel housings, and is made for heaters only. The overall diameter of this split nut is 3-3/8 inches. This split nut will fit Balboa, Brett Aqualine, Cal Spas, Gecko, Gulf Coast, Hydro-Quip, and many others with metal 2 inch heater assemblies.
Note: The 2.0" is not the actual measurement but a representation of the inner diameter of the plumbing that is used.