Seiko/Credor Spring Drive
A spring-drive watch with quartz accuracy
Wind system: Hand winding
Accuracy: Within +/- 15 seconds for rate (+/- 1 second for daily rate)
Wind-up life: 45 hours
Dimensions: Diameter - 29.0 mm; thickness - 3.5 mm
Waterproof level: Water resistant in daily use (water resistant to 30 m)
The design of the Spring Drive's movement drew on original Epson technologies and included a groundbreaking mechanism. This limited-edition watch was first sold in 1999 under the Seiko and Credor line, Seiko's luxury watch brand. It was hand-wound and spring-driven like a mechanical watch, yet it was controlled by a crystal resonator for outstanding, quartz-like accuracy.
While the power source and train were identical to those used in mechanical watches, the Spring Drive was accurate to within a monthly rate of +/- 15 seconds (equivalent to a daily rate of +/- 1 second) and featured a sweep second hand.