BEWI Belichtungsmessgerät 1930 Light meter

Original Präzisions Belichtungsmesser with box and instruction (in German). Made by Paul Will in München Germany.
The BEWI lightmeter dates back to 1930. After setting the film speed in Scheiner (A = Autochrome plate and 1 to 27°) on the front detent scale, the reading on this scale is adjusted to an arrow mark by rotating the lightmeter body. The exposure values can then be read in a window below the arrow, next to the aperture settings.