In Lieu of a battery it's run by a small solar panel on the watch face (the 'Eco Travel') and due to 'Atomic Timekeeping' it could claim for being the 'most correct watch in the world'. NOMOS is really a member from the Deutscher Werkbund, a Bauhaus initiative of companies https://www.watchesworld.com/germanys-top-10-favourite-luxury-watches/