The Girard Perregaux 47BF watch movement was produced during the period of 1966-1970. It features an indirectly driven minute and automatic gear integrated into the movement, enabling a low profile design. The movement includes a ratchet on the dial side and a crown mechanism with a rocker bar. Furthermore, it incorporates a rather small rotor ball bearing. Details regarding the differences between the 387 and 389 models are not available. The Girard Perregaux 47BF movement includes functions such as automatic winding, sweep seconds, quickset date, and is meant to be used for a specific period from 1966-1970.