Weston Direct Reading (DR) Exposure Meter Model 853. 1954, USA Manufacture.
Very compact in design, this model dispenses with the scrolling display of the two earlier models. A rotating blind over the cell on the reverse (illustrated below) sets the film speed by effectively desensitising the meter's response to light.
The Meter face is marked up directly in f stops (lens aperture). This corresponds to a reference shutter speed of 1/50th second, highlighted on the table on the front of the meter. Additional aperture settings can then be read off for other shutter speeds from 1/10th to 1/200th second.
There is no support for shutter speeds outside of this range, though an experienced photographer could easily extrapolate the values they would need. The smaller scale of numbers on the lower part of the scale are light values. There is no apparent reason for their inclusion since there is no other reference to them on the meter.
This model of Direct Reading meter is frequently seen for sale in presentable condition (if not actually working). The earlier 850 and 852 models, much less so, since the scrolling displays have, in the main, disintegrated over 75 years of existence.
The film speed setting blind on the rear of the Model 853 Direct Reading exposure meter.