Anvil 8700157954, Steel Pipe Fitting, Coupling, 1/4" NPT Female, Black Finish: Amazon.com: Tools & Home Improvement
Value Collection - Black Female Coupling: 1-1/2″ - 51260537 - MSC Industrial Supply
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
Orbit Barbed x 1/2-in FNPT Flex Pipe Coupling in the Flex Pipe Fittings & Risers department at Lowes.com
Southland 1-1/2 in. Galvanized Malleable Iron FPT x FPT Coupling Fitting 511-207HN - The Home Depot