You are buying a Set of (2) 2" Heater Split Nut with 2" Slip X 2" Thread Heater Union Kit which includes (2) Split Nuts , (4) Screws, (2) 2" Slip X 2" Threaded Unions and gaskets for use with a 2" Heater Union as well as (2) 2" Slip x 2" Street Slice Gate Valves. The Heater Flange Split Nut mounts to the heater tube using 2 screws to hold it in place and screws onto the heater threaded union with a gasket between the union and tube. If your plumbing is 2" which Measures 2 3/8" Outside Diameter and your heater is 2" which measures 2" inside the tube and the threaded part measures 3" Outside Diameter then this part is correct. This version is the most popular version. 1 1/2 x 1 1/2 is 2nd most popular and 1 1/2" X 2 is 3rd most popular.This part is used in hot tubs to plumb a heater tube to a heater union. Note: The Heater tube in pictures is NOT included!! Note: We have a You Tube Video about this part. Look for "Hot Tub Spa Part 2" Heater Split Nut Information How To The Hot Tub Professor" PLEASE NOTE: We did a lot of extra work with pictures and measurements so please do your part and measure your old part to be sure it is correct.. This will save us all some time and money.. Thanks.. Note: Colors May Vary it could be white or black pvc..