Rolex Bubbleback
The early self-winding Oyster Perpetuals, with a domed caseback that made room for the rotor.
The nickname Bubbleback comes from the bulging caseback. These were Rolex's first self-winding watches in larger series and have become popular with collectors.
Materials: Steel or gold; self-winding movement
Manufacture: Made in Geneva from the 1930s to about 1950.
The domed caseback visible from the side.
The small, round Oyster case.