My plumbing originally had black plastic fittings in the PEX tubing, they eventually became brittle, cracked and all the fittings had to be replaced. I used brass fittings, (elbows, "T's" etc) and the SS "cinch" clamps. Much easier to use than the copper clamp rings, and have been very durable..
This site shows a newer plastic fitting and it may hold up better than those on my MH.
PEX fittingsThe black plastic did not tolerate chlorine.... The sharkbite or gatorbite fittings are excellent for quick repairs but bulky and expensive for extensive use.
