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
BMI USA Malleable Iron Pipe Coupling 2-COUPLING Hydraulic Supply Co.
FBRI2 - Ward FBRI2 - 2" Black Right & Left Hand Thread Coupling
Sigma ProConnex 2-in Zinc-plated Steel Threaded Coupling Conduit Fittings in the Conduit Fittings department at Lowes.com