The Argus A2B was like the Argus A, but had a built-in extinction meter and exposure calculator. It was produced from 1939 thru 1950, originally costing $12.50.
Argus of Ann Arbor, Michigan, held two U.S. patents on it, one on the 35mm camera type for built-in pop-out lens tube with a simple bayonet locking mechanism, invented by Argus' founder Charles A. Verschoor (probably with help of his engineer Gustave Fassin), and one on the extinction meter with exposure calculator, invented by W.F. Carr.
The Camera has a 50mm f/4.5 coated Anastigmat made in USA, mounted in a shutter/aperture assembly with nine-blade diaphragm for apertures f4.5 to f18 and everset shutter with T an B mode plus the speeds 1/25, 1/50, 1/100 and 1/150 sec.. Other sources report A2B cameras with Ilex shutter (1/200 sec. max speed), maybe the pre-war variant. An exposure counting wheel on the camera's top is driven by the perforations of the 35mm film. On top are also the film advance wheel, the advance-to-next-frame unlock button, the reverse Galilean viewfinder, and the meter. The meter has a broad window through which more or less of the extinction meter's more or less translucent foil pieces become visible, depending on the light situation. The exposure calculator's big shifter on top of the meter must be shifted as far right as light is visible through that window. Then the lower end of the little shifter must be shifted so that it points onto the word for the light situation ("bright", "average", "cloudy", or "light int."). Then the possible appropriate shutter-speed/aperture combinations can be read from the little shifter's aperture scale and the speed-table column left to it. The bakelite camera has a removable metal back door. With some nicely chrome plated metal parts around the lens barrel and decent art deco styling of body and back door the camera is one of the beauties of U.S.-American viewfinder camera design.