Citizen Men's BL5370-51L Eco-Drive Perpetual Calendar Chronograph Sport Watch Light powered Eco-Drive Caliber E81* Japanese-quartz movement; Charges in natural sunlight or indoor light Max power reserve: 120 - 270 days with Power Save; Low charge warning: 5 days; Charge time from stop state to max charge: Incandescent Light - 43 hrs, Outdoors, Cloudy (10,000 Lux) - 12 hrs, Outdoors, Sunny (100,000 Lux) - 4 hrs Durable, hardened non-reflective mineral crystal; Case diameter: 46 mm; 1/20 second chronograph measures up to 60 minutes; 12/24 hour time with 24-hour subdial; Dual-time function Stainless steel case and matching bracelet; Dark-blue dial; Perpetual-calendar function; Alarm function; Screw-back case Water resistant to 660 feet (200 M): suitable for recreational scuba diving