SW500 M BV b

This cam-actuated chronograph features dual push-buttons, central 60-second timing, and registers for 30 minutes at 12 o'clock (or an optional 15-minute version) and 12 hours at 6 o'clock. It includes manual winding, a date with quick-set, a stop-second mechanism, and beats at 4 Hz with 21 jewels and a 63-hour power reserve.