Horiznext npt 1/2 (means the inner diameter of the thread is 3/4 inch) cast female taper threaded pipe coupling, stainless steel 304 coupler for mush tun cooler and shower hose, 2 pcs - Amazon.com
External Coupling, 1 1/2 in For Pipe Size, Structural Pipe Fitting - 4NXU9|4NXU9 - Grainger
Southland 1/2 in. Black Malleable Iron FPT x FPT Coupling Fitting 521-203HN - The Home Depot
1 1/2 in x 1 1/2 in Fitting Pipe Size, Schedule 40, Coupling - 22FJ43|429015BC - Grainger