Hopefully Marc is still tuned in, or maybe someone else knows.

How are the 522C (for Canon) and the 523PRO different? They look the same in the B&H pics.

And will they fit a 116 head?

[Edit: Ah, I see that the info is up on Manfrotto.com. I thought I saw in another post that it wasn't. But I'd still like to know if it will fit my 116 head]

Yes, the 522C and 523PRO will fit your 116 head.

Marc Schotland
Manfrotto

My head has a 15mm adjustable pan bar. I can't find information on what heads the 523PRO is compatible with or what diameter it's bar is. Far as I can tell, it seems the 523PRO is built to use the existing head's clamp.