Spring Drive Watches
Spring Drive is a unique technology developed by Seiko that combines the traditional mechanical watch movement with electronic components. In a Spring Drive watch, a mainspring powers a traditional mechanical gear train, but instead of a traditional escapement to regulate the movement, it uses a quartz oscillator and an electromagnetic brake to regulate the speed and accuracy of the watch.
This allows Spring Drive watches to have the smooth sweeping second hand of a mechanical watch while also maintaining accuracy comparable to quartz watches. The technology also allows for a power reserve of up to three days.
Spring Drive watches are considered high-end luxury timepieces, and are produced by Seiko's high-end watch division, Grand Seiko. The technology is also used in some other Seiko and Credor watches.