Agfa Lucimeter -S, type 6380
Analog. Agfa was a major German manufacturer. This one is from mid-50s
Though used, it was well-cared for. The plastic holding case is cracked - not the casing
How to use it: it uses a selenium cell so no batteries to deal with. Aim it at your subject and notice that the needle swings to the right. Rotate the outer ring on the calculator dial and you'll see the diamond-shaped needle move. Move the diamond needle so that the other needle is in the middle—this is called matching the needles. Once they're matched, you can read the speed/aperture combinations in the lower half of the calculator.