vintage photography equipment, 1940s 50s General Electric light exposure meter

Nice all metal housing on this vintage light meter - it's a GE exposure meter, 1940s or 50s I think. Looks very good, clean, dial moves smoothly.I don't know how to work with an old fashioned light meter, and I'm not sure how to play with the dial for different settings. But the needle when wild when I stepped from the shade out into the sunlight, so I think this works!