There are several PEX supply connection methods, but only two affordable enough to be practical for DIYers: crimp rings and cinch clamps. Crimp rings are a band of metal, usually copper, that you slip over the fitting and compress with a crimp ring tool.

A push-fit fitting uses metal tines to hold the tubing, in this case PEX and copper, against an O-ring seal. The fittings are sized by the tubing’s outside diameter. A clamp-ring connection connects PEX to existing metal pipe. PEX tubing is crimped onto the male end, and the female end is either soldered or threaded onto existing pipe.