You are buying a 1 1/2" Heater Split Nut Only which includes the split nut and (2) Screws for use with a 1 1/2" Heater Union. 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. Please see our store for a kit that includes the gasket. If your plumbing is 1 1/2" and your heater is 1 1/2" this part is correct. This version is the second most popular version. 2 x 2 is 1st 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. 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.. See our YouTube Video on this product. Search for "Spa Heater 1 1/2" Split Nut Information How To Hot Tub Parts of America"