NIBCO 3/4 in. CPVC-CTS and Brass Slip x FIPT Transition Union C4733-3 - The Home Depot
Sharkbite 3/4 x 1 Inch FNPT Water Softener Adapter, Push to Connect Brass Plumbing Fitting, PEX Pipe, Copper, CPVC, PE-RT, HDPE, U086LFA, Pipe Fittings - Amazon Canada
Nibco Part # C47333LFHD34 - Nibco 3/4 In. Cpvc-Cts Copper Silicon Alloy Lead-Free Slip X Copper Silicon Fipt Transition Union - Cpvc Adapters - Home Depot Pro