Self-winding - chronograph
Cam operated chronograph - two push-buttons
Hours and minutes
60 seconds counter in the center
30 minutes counter at 12 o'clock
Optional: 15 minutes counter at 12 o'clock (SW501 BV c)
12 hours counter at 6 o'clock
Self-winding mechanism with ball bearing
Stop second device
28'800 vibrations per hour (4 Hz)
25 jewels
Typical power reserve: 62 hours
