PEX Connections

I have a PEX pipe coming out of my slab that has a black interior, a shiny metalic layer, then a gray outer layer. I'm assuming it's the aluminum oxygen barrier PEX. The outside diameter is .9375 (15/16") so the 3/4" crimp rings I get at Lowe's will not fit.

Note: it appears that the outer layer of gray has been removed to put a fitting on originally. Experimenting with the pipe and removing the gray puts the metal layer at just over the .875" that is specified for 3/4" pipe. I can't believe that this is the right way to terminate the pipe.

What kind of crimp rings are supposed to be used for this pipe?

The fittings and crimp rings made FOR it. It is probably Pex-Al-Pex which was normally only used for infloor heating systems. Hopefully your brand is still in production, because some companies have abandoned the material.

I talked to a couple of different plumbing houses today and found out that the pipe is Viega Pex. Also found out that as part of the fitting installation a "reamer" is used to reduce the outside diameter of the pipe. I don't know anything about Viega yet, but I'll read up on them.