The pusher is a sort of « flyback » functionality for the second hand. This GO caliber (ref 100-0x) is non hacking. Pulling the crown outward does not stop the balance wheel. GO watchmakers thought about this as an alternative to the traditional hacking second system to reduce the natural wear and tear that is caused by stopping/restarting the balance wheel many times over time. I’ve been told this movement could easily go 5 to 7 years with no service. I can’t really say if this is true as I tipically have my watches serviced every 3years regardless. There another integrated pusher at 2o’clock for the panaroma date.