Working Vintage Arnold Guage.
Measurement range1 3/4" - 4"
Federal c5m Indicator. Cloudy lens. Some paint loss on dial face.
I tend to leave things as I find them, although, I think headlight cleaner should clear up the lens and some clear poly spray should stablize the paint on the faceplate.
The Federal c5m is fairly inexpensive here on ebay if you would rather replace it.