Once confined to women's watches, quartz movements have prompted a number of surprising new developments in Fine Watchmaking of late. Piaget's engineers started out with a traditional mechanical movement, with an off-centre micro-rotor to wind the mainspring and a conventional gear train. Its force is regulated not by the usual balance-and-spring assembly but by a miniature generator which, as it turns, produces an electric current. This acts on a quartz timing package which regulates the generator's rotational speed of precisely 5.33 turns/second. The principle behind this type of hybrid movement, implemented for example by Seiko, builds on an original concept that was registered in 1972. Piaget spent two years stabilising this movement.