Or something that looks like one...
CLICK on the links to find the charts!
I know, I know, those comparison charts you find online don't make any sense...
Ours doesn't as well!
The problem is that each maker uses different bites, measures diameters at different heights, weight, throats and backbores play a role on how you perceiver a mouthpiece and so on.
This very short comparison chart is a guide line: none of my mouthpieces feel or sound like those in the chart but I know the brands I listed enough to have developed a good "feel" for them.
So, you have to trust me!
The best starting point when you ask me what to buy is to refer to Bach sizes, they are by far the less consistent but most of us started with them so we have at least some common ground.