Pex and copper have the same O.D. you can use the same sharkbite fitting on both types of piping.
Yes, that's true. One thing to remember however is that you should use the stiffeners that come in the sharkbite fitting package ONLY with pex. I've heard, but never witnessed, that it can cause leaks when used with copper.
Did not know that at the time, but yeah it looks like they are compatible. Figured the ends were made different. Somehow, I would not really trust them on copper though... but seems to be what my contractor used for the kitchen, so guess it is accepted. I did not figure the teeth would be able to actually dig in solid enough into copper.
The new PRO-PRESS fitting system for copper utilizes a similar function for it's fittings.