Instead Of a battery it's powered by a little photo voltaic panel around the watch face (the 'Eco Push') and due to 'Atomic Timekeeping' it might claim being the 'most correct watch on this planet'. If what is going on in Neuchâtel and Program-les-Ouates is anything to go by, Patek https://www.watchesworld.com/germanys-top-10-favourite-luxury-watches/