Here is a 1906 Dueber Hampden lever-set seventeen jewel "The Four Hundred" pocket watch movement re-cased back in the day as a wristwatch. It's going off to the watchmaker next week for a new crystal. It measures 31mm in diameter, 37.5mm lug-to-lug, and 10.5mm thick case back to top of the crystal.
For those not familiar with lever-set movements, the time is set using the crown, but rather than the crown being pulled out and away from the movement to activate the setting mechanism, instead a lever at the "five o'clock" position of the movement must be pulled out. The photos below show the lever in both positions.
For the history minded.....Dueber was an Ohio based watch case manufacturer that ran afoul of the powerful U.S. watch trust in the late 1800s, and was boycotted by the trust's members. In response, in 1886, Dueber purchased one of its customers, the Hampden Watch Company of Springfield, Massachusetts.
Dueber then moved six hundred Hampden employees and their families, and Hampden's equipment, to a new factory in Canton, Ohio. As noted in one of the DH advertisements below, this move created "The Largest Complete Watch Factory in the World" -- i.e., DH produced movements and cases in the same facility, while most watch companies of the time manufactured movements and bought cases from outside vendors.
During the transition period between the popularity of pocket watches and the predominance of the wristwatch, companies sprang up that offered conversion kits that allowed pocket watch owners to convert their pocket watches into wristwatches -- the kits typically included a wristwatch case and conversion dial. An advertisement for a conversion kit for DH pocket watches appears below.
Although Dueber Hampden went on to make complete wristwatches, it ceased operations in 1930 when it was purchased by the Soviet Union state owned Amtorg Trading Company. Amtorg relocated DH's equipment and work in progress inventory to Moscow along with twenty-one DH employees to teach the art of watchmaking -- thus was created in1931 the First State Watch Factory, the basis of the Soviet watch industry.