There is no single fitting currently available that can connect PEX directly to PVC. Push-fit fittings such as SharkBites work with PEX, copper, and CPVC — but not with PVC pipe (Schedule 40, Schedule 80, DWV, etc.). The best way to make a PEX to PVC connection is with a pair of threaded adapters. Use a PVC socket solvent fitting with male threads and a PEX fitting with female threads. The PEX x FNPT adapter can be in any PEX fitting style (crimp, ProPEX, PEX Press, push-fit, etc.). Try to have male threads on the plastic fitting when you connect plastic threads to metal threads in order to minimize any risk of cracking the plastic threads. If, for example, you need to connect 3/4″ PEX to 3/4″ Schedule 40 PVC and you prefer to use SharkBite fittings on the PEX side, you can use parts 436-007 and U088LF.