FG Auto-Dim mirror question - button or no button???

[pezcat19]

Hi all,

Just a quick question: I'm going to add a Auto-Dim mirror for my 2011 MK1 FG F6, but I see that Ford seem to have put 2 different versions in the FG's...

One has a power button on the front, and one doesn't.

Can anyone tell me what is the best version to go for? And, what does the button actually do?

Thanks in advance!

Pez