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
NIBCO 2 in. ABS DWV Hub x Hub Coupling C5801HD2 - The Home Depot
Fernco 2-in Schedule 40 PVC Coupling in the PVC Pipe & Fittings department at Lowes.com
2 in. External Furniture Grade PVC Coupling - White | FORMUFIT
Amazon.com: Horiznext npt 1/2 stainless steel hex pipe fitting, 3/4 inch male thread O.D. water hose connector, for valve shower faucet tube air gas line plumbing coupler extension.(4 pcs) : Industrial & Scientific