Well.. I thought it was PEX until I read this thread. Ooops!
Anyway - it has worked great so far. I never checked the PSI - I also bought and installed a new water pressure regulator for hooking up between the hose and city water inlet. (just to be sure)
I cheked the line - it is stamped with: "1/2" BRAIDED PVC" (which is 3/8" inside and 5/8" outside) - so this hose was pretty thick (when you cut it you can see the cross section that has the fiberglass threads in the middle of the plastic hose). They have several sizes -> maybe thicker = more PSI tolerance? I just bought what seemed right to me.
The fitings are either the plastic (I think QWEST) or regular brass - just use a barb ending (looks kinda like a pyramid with steps). The hose just sweezes on and is secured with a clamp. Same thing for the tees - just get three barb ending tees.
I never thought about it before - but you could go nuts and untighten the clamps and remove any horizontal hose and lift one end - they'd be winterized
You can also use brass - bard at one end to a copper compression clamp (with the little O ring inside that gets tightened down on the copper line).
For faucets / fixtures, I just used regular faucet hook-ups available with any basic plumbing supplies. The ends are usually 3/8" and you can hookup the female end of the hook-up to a male screw brass fiting with a barb. So its hose- clamp - barb - male brass - female (usually plastic) faucet hookup. Works great on hot or cold - sink / vanity or shower.
All fitings, clamps and hose I got at Home Depot, but Menards carries everything as well. One may not have the correct size fiting you want and you have to go somewhere else to get it.
If you can play with legos or lincoln logs - you can do this kind of plumbing. And it is really easily repaired / replaced or rerouted.
The REAL challenge is getting to or getting elbow room along the plumbing lines in the trailer!
Also - buy some nail or screw down clamps for the hose and place them at strategic spots (like before and after bends).
One last note - a plumber friend of mine said this would work great - he fixed all my house plumbing and does this for a living so I figured my trailer would be ok. He also said the plastic gives more than the copper and resists the expansion / leaks that improper winterizing causes with copper.
I leave with a puzzle - I had intended to do all copper lines. The problem was the copper in the trailer (numerous leaks and splits) was in only a FEW spots 1/2" but most everywhere expanded just beyond 1/2" and absolutely WOULD NOT fit with 1/2" fitings. I can NOT tell if it is from SEVERE freezing or just weird copper tubing. Did A/S use something special? The copper is marked: " 1/2" TYPE L H.M.P. MADE IN THE USA".
So I cut out what I didn't need and got to the sink fitings which were standard faucet hook-ups someone else had put in. That started me thinking about the fiberglass hose.