Prospex Speedtimer Solar Chronograph Design inspired by Seiko's 1969 Speedtimer, one of the world's first automatic chronographs 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 Blue dial with sunray finish and red accents Date calendar 24-hour subdial LumiBrite hands and markers Curved sapphire crystal with anti-reflective coating on the inner surface Dual-tone red and blue tachymeter bezel Screwdown caseback Case diameter: 41.4mm Stainless steel case and bracelet Tri-fold push button release clasp Water-resistant to 10 bar, 100 meters (330 feet) Caliber V192