The terminology for the piece which is used to fasten the fitting to the tubing does not seem to be standardized amongst retailers. I'm confused by the non-standardized usages of the terms crimp and clamp; sometimes phrased as "crimp ring" and "clamp ring," as opposed to "compression ring."
Omitting the fitting that is inserted into an expanded tube which then shrinks back around it:
AFAIK there are:
1 COMPRESSION RINGS; made of copper, which use a unique tool and a gap gage to verify adequate compression. The ring is a solid band. Some are colored black to mark them as being for use with the obsolete polybutylene (PB) pipe.
2) CLAMPS, made of stainless steel, which use a different unique tool that ratchets until it is tight enough. See
3) Oetiker Stainless Steel Crimp Ring, which might use the same tool as 2 or not, I'm not sure. See:
Does "SSC" (stainless steel clamp) refer to just 2) or both 2) and 3) ???
I have also come across references to a fastener/tool where you have to "snip" a tab before using the tool to tighten it.
Using all 3 items (pipe, fitting, fastener) from one manufacturer is prudent, but since I have not decided which brand to use, I'd really like to see a table showing various manufacturers stuff, with the trade name they use, divided into the categories of fasteners.
Does anyone make plastic fittings usable with the clamp type fastener? Looks like Watts "Poly-Alloy" plastic fittings are only to be used with the Compression Rings. Their brass fittings can be used with either.
My acid water makes me want to go all plastic, but I think the skill level of the crimp fastener is easier to succeed with than the compression rings. And the tool is much cheaper.