The face is about 3", the back is about 2 3/4", and it has a 270° sweep (more accurate than 90°). I'm not sure if it is lighted or not, but there is a hole in the back that looks like a light can go in it, but there is no light in the package...
It's an old Sun gauge made here in Chicago. I bet my uncle knows exactly where that was, as he's from that area...
If you don't want it, that's fine, I'll keep it for myself. But you requested it, that's part of the reason that I bought it. (a little more than you said, but reasonable price). I bet this is better quality and will last longer than a new one made today (from China)...