Made in Japan, I purchased it on one of my travels in Germany, back in the early 2000’s. I am told this was produced around 1957, with the intent to be clipped onto the hot shoe fo the cameras. As I never grew to like top plate meters, I always used it as a second meter with my Minox cameras. It is not so handsome now, but it was a beauty then. It’s battered, needs a good CLA, but it performs like no other.
Made from metal, the rotating discs are brass. The flap closed for day light, flap opened for low light. ASA settings starts with 8 to 800, it’s a needle reading meter, so you just follow the needle, into a zone (1 to 7), see the numbers, transfer the number to the dial and you have your shutter speed.
This will also will show you the light value (not the EV, mind). Shutter speeds: 4, 2, 1, 1/2, 1/5, 1/10, 1/25, 1/50, 1/100, 1/250, 1/500 and 1/1000, whereas the f-stops count from 1, 1.4, 2, 2.8, 4, 5.6, 8, 11, 16, 22 and 32. I would say you’re covered.