Amazon.com: SharkBite 3/4 Inch x 1/2 Inch 90 Degree Reducing Elbow, Push to Connect Brass Plumbing Fitting, PEX Pipe, Copper, CPVC, PE-RT, HDPE, U274LFA : Everything Else
Brass Push-To-Connect Fittings, Valves & More ǀ SharkBite
Pro-tip: Thinking of using Pex-A? Avoid Sharkbite (brand) brass fittings (found at some Lowes). The tiny shoulders make it next to impossible to get a proper fit on 90's and Tee's. :
Connect PEX to Copper, Replace Copper with PEX | SharkBite