This part is a 2" Slip which measures about 2 3/8" ID X 2" which measures about 3" OD Heater Union without a Groove for a Ribbed Gasket or O-Ring. The Union receives a 2" pipe or fitting on one side that measures about 2 3/8" Outside Diameter and then Screws to a 2" Heater Flange Split Nut on the other side that measures about 3" on the outside of the Threads. This part is used in hot tubs to plumb to a heater flange.
You would use this Union with a Flat Gasket Found Here: Flat Gasket, 2", Pump Union, Heater Union
