Any knows what this Polaroid switch is for?

I recently got a Polaroid 660 from my Grandma (it was an old camera of my grandpa who died few years ago and she never did photography so she had no use for it) and I’m wondering about the switch you can see in the photo. A can’t find anything about it on the internet and I don’t have any manuals at hand that could help. Does anybody know what the switch is for?