I'm trying to connect some 1/2" Pex A to this gray piping. I have never come across this stuff. What is it and what type of fitting do I need?

Thanks.. BP...

Polybutyl
Fitting looks like Qest
Sharkbite makes a transition fitting or you can get crimp adapter.

This ^^^
It's crap. If possible, get rid of it.
Our main line was Quest piping and it eventually started leaking.

https://nicholsandphipps.com/plumbi...oly,raw%20material%20for%20the%20piping.

Yep Butyl.
Sharkbite makes a transition ,or they make pex-B crimp style connectors.
Depending on what you are doing they also still make Quest connectors like you have.
The pex couplings have a little different set of ridges,but the ring is the same.
https://www.ebay.com/itm/132260329654?_trkparms=amclksrc%3DITM%26aid%3D1110006%26algo%3DHOMESPLICE.SIM%26ao%3D1%26asc%3D264183%26meid%3Da2450e24637842f0a8ce

I hope this PB isn't connected to a chlorinated water system. From what I've read, they didn't test the stuff with chlorinated water and a lot of it got installed before it was learned that chlorine will kill the tubing. I have PB but I'm on well water.

Sharkbite fittings work but don't use them where you can't get at them later. I've never had one fail but they aren't as strong as some of the compression type fittings.

Second that one. Most insurance companies will not cover water loss associated with polybutylene pipes. That should tell you everything you want to know about polybutylene.

Looks like you are basically trying to connect 1/2 (IPS) size to PEX (CPS) size material. Like everyone else said Shark bite has options but make sure they aren't in a bind when put together cuz they will start leaking. They have a fairly "thin" o ring for seal compared to some of the brass compression fittings that have thicker beveled gaskets in them.

If you have the crimpers, this fitting is made to connect PB to Pex.

LINK

I wired houses in the San Diego area back in the mid to late eighties. Man, there was miles and miles of Quest piping in those houses. I feel sorry for those homeowners.

Thanks all. This is on a well and it was a repair the previous owner made. There are 2ea 4ft pieces that connect to my hot and cold shower water. This will be a temporary fix till I can remove some outside siding to access the shower faucet and the short pieces of this tubing.

PB...