Citizen Men's BL5184-56L Eco-Drive Perpetual Calendar Two-Tone Watch Light powered Eco-Drive Caliber E811 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 mineral crystal; Case diameter: 40.5 mm Two-tone stainless steel case; Blue dial; Perpetual calendar, chronograph function Water resistant to 330 feet (100 M): suitable for snorkeling, as well as swimming, but not diving