Hi Daddyandsage...

PEX crimp rings are manufacturer specific... no exceptions! You must use a specific crimp ring and tool with a specific pipe type.

In this case, unless the manufacturer says it's OK, do not use PEX anything with polybutylene pipe.

Mark

I am left wondering why on earth would anyone be working with polybutylene. The only time poly comes up is when it must be removed. Hasn't been made in about 15 years if I remember correctly