Terry sharkbte makes a transition coupling ftom poly to pex. They are a little hard to get. Either model u 4008 or u 4016. The poly side of the fitting is grey, not gold like regular sharkbite. They also make transition pex crimp fittings, that I can usually find at lowes and plumbing supply. They come with rings, but you can use the stainless cinch rings in their place.