This is the newest material to come on the market in response to the problems with Poly. It is expensive but good. Unlike PVC, it can be used for hot water lines. I see it in the home improvement places. I have used CPVC frequently in the past. PEX is especially valued in parts of the country where water lines frequently freeze for its ability to stretch without splitting.
PEX is increasingly available in the chain home improvement stores. They may have a few pre-cut pieces and connectors, but will not have what you need for a plumbing project on your mobile home. You will need to visit a mobile home supply store to get the assortment needed for completing a project.
