Huh, I always thought this watch was larger, but I just measured it....case diameter w/o crown 33.75mm....lug-to-lug 41.35mm....18mm band...1950s Unitas chronograph with a Venus 210 movement.
have a look at this original dialed 1954 Oyster. We see the shadows around the radium plots. Unusual is the german writing: "amtlich geprüfter chronometer" instead of "officially certified chronometer"
(A note to those who are in the market for watches in this category: I am going to be listing a few for sale, including a UG today. So keep your eyes on the Sales Forum, and if you are really hungry, feel free to PM me. 😉 )