I was looking at the PEX clamps and tools at the Hardware store. There
are two types of clamps, and each uses a different tool.

One is solid ring which says it's copper, even though it's black
colored. It appears that the whole ring gets crushed to a smaller size
from the tool.

The other is silver colored and is supposed to be stainless steel. Those
have a "nub" that sticks out and it appears that the nub is what gets
compressed.

A store worker came over and asked if he could help me. I asked him
which clamp type is the best. He said the stainless steel ones are best.
But he was a young kid who did not appear to know anything about
plumbing or any home repairs. The stainless steel clamps are
considerably more costly, so I suspect he just based his answer on the
price. (Assuming more expensive means it's better).

I've got a small plumbing project to do in the future and am considering
PEX, but I want the best clamp, even if it costs a few dollars more. So,
before I buy the tool, I want to make sure I know which clamp type is
the best.

That guy told me that they rent the PEX clamp tools, but when I asked
the hourly price, I may as well just buy the tool, and wont have to rush
to get the tool back to the store to save money on the rental cost. One
day's rental is nearly half the price of buying the tool, and I hate
being rushed when I do any projects. I'll either save the tool for a
possible future plumbing job, or I can sell it online when I'm done.