Prospex LX Sky Limited Edition. Designed for those who treat life as the ultimate adventure, the Seiko Prospex line meets every challenge with technological excellence and style. Part of a rich legacy of innovation in high-intensity timekeeping, Prospex continues to celebrate a long history of sports watch excellence with recreations and reinterpretations of landmark achievements. This extraordinary watch, available only in a limited edition of 400, with the serial number engraved on each caseback, highlights both past and present feats, with a design inspired by Seiko's revolutionary 1968 professional diver's watch, but powered by today's Seiko Spring Drive movement, combining a 30-jewel automatic movement with a quartz regulator for accuracy to +/- 1 second per day, +/- 15 seconds per month. With the Spring Drive movement tested for precision by astronaut Richard Garriott on the International Space Station, this limited edition also pays tribute to space exploration with the blue and black gradated dial and sapphire bezel ring evoking the stratospheric boundary of the Earth's sky and outer space. Crafted of light and durable titanium with a super-hard coating for nearly doubled hardness, this superbly reliable watch features a sapphire crystal with super-clear coating, and a screwdown caseback and crown, as well as a tri-fold push button release clasp. The movement, with a power reserve of approximately 72 hours, can be wound manually or automatically. Framed by a rotating GMT bezel, the dial includes a power reserve indicator, date calendar, blue GMT hand, and LumiBrite hands and markers. Water-resistant to 10 bar, 100 meters (330 feet)