3/4" x 1/2", evopex push to connect reducing coupling, high performance polymer with great chemical & chloramine resistance, no tools, no calibration, no rings for error proof installation, can see visual indicator for assurance of proper fitting connection, easy install, no potential for leaks caused by nicks on the fitting exterior, 200 degrees maximum temperature, 160 psi, listed by iapmo & design certified & listed to asse 1061, nsf 61, meets all upc, ipc & cupc requirements, no de mount clip required, not meant to be removed once installed.