Design inspired by Seiko's 1969 Speedtimer, the world's first self-winding chronograph Powered by light energy - no battery change required 6-month power reserve once fully charged Chronograph measures up to 60 minutes of elapsed time in 1/5-second increments with split time measurement function Pale blue dial with sunray finish Date calendar 24-hour subdial LumiBrite hands and markers Curved sapphire crystal with anti-reflective coating on the inner surface Black tachymeter bezel Screwdown caseback Case diameter: 39.0mm Stainless steel case and bracelet with gray inner links with a hard coating Tri-fold push button release clasp Water-resistant to 10 bar, 100 meters (330 feet) Caliber V192