Citizen CC3020 57L Men's Satellite Wave World Time GPS Blue Dial Steel Bracelet Watch ASIN B0091V9J3I approximately battery operating time: 8 approximately battery operating time: 8 months on rechargeable battery (operation period with normal use without exposure to light after charge) 19 months on rechargeable battery (operation period when stored in total darkness with the power save function on after full charge) Christian Paul GR 02 men's Bridport Grid white accent black dial brown leather strap watch is offered Citizen CC3020 57L is powered by Japanese F150 Eco Drive (Eco Drive is fueled by light so it never needs a battery change) movement scratch resistant anti reflective sapphire crystal and water resistant to 100 meters