Power Source and Battery Life Approx. battery life: 3 years on SR621SW Glass Mineral Glass Back Cover Screw Lock Back Band Size 150 to 205 mm Moon Data Moon Phase Accuracy Accuracy: ±20 seconds per month Other Features Display Time: Analog: 3 hands (Hour, Minute, Second) Case Size (L × W × H) 48.4 × 42.5 × 9.6 mm Weight 113 g Watch Size: 48mm Brand: Casio