It's an automatic movement with no rotor. Has a section of the movement the go back and forth bumping back and forth to wind the movement. When you wear the watch you can actually feel a slight bumping action of the movement !
No...they have rotors, but they don't rotate 360°. This was because Rolex had patented the full-rotor automatic, and other manufacturers had to wait for the patent to expire. The work-around was to create a modified movement.
Thank you for this information. This is a piece of history I didn't know. When did they patent automatic movement and when did the patent expire?
Also. Since now a days bumper watches are not popular, is it safe to say automatic watches were technically superior?
Correct. The notable disadvantages is that full-rotors are more efficient, and can bear more (rotor) weight. Began in 1931, expired sometime in the early/mid '50s.