Halex 1/2 in. Rigid Conduit Coupling 64005 - The Home Depot
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
Aluminum, 1/2 in x 1/2 in Fitting Pipe Size, Straight Coupling - 60PV88|ZUSA-PF-9382 - Grainger
ZUSA-PF-93 | Pipe Fittings - Coupling, Female NPT, 304 Stainless Steel, Class 150 | USA Industrials | MISUMI