A watch will sometimes gain even when the regulator is pushed as far as possible towards "slow." The regulator of every watch is provided with two curb pins, between which the outer coil of the hairspring passes, and in the case mentioned it may be found that the hairspring does not vibrate freely between the curb pins, but binds against one of them. If it already vibrates, opening the curb pins to give more play will cause the watch to go slower.