This is a very heavy meter made of metal finished in black crackle paint. In use the finder focuses on a screen having on it a dot formation, half of the field remains brighter than the other to prevent false readings due to eye compensation. The meter knob is turned, which rotates a variable density wedge, until the dots on the darker half of the field merge with the background. The density wedge is made of two pieces of photographic film.

In use the calculator is set to show the film speed. The exposure number (least distinguishable in finder) is set against the weather condition. The shutter speed and aperture pairs can then be read. A note in the instruction book says the meter was planned in 1940 and that in 1945 sample models were produced.

In use the least distinct letter in the finder is set against the film speed. Adjustment is made for the weather conditions. The shutter speed and aperture pairs can then be read.