Corum Watch AC-One Openworked Tourbillon A298/03899. Corum is proud to contribute to perpetuating the time honored values and expertise of Fine Watchmaking. Corum has adopted creativity and boldness as its guiding principles. It is pursuing the path traced by the founders, more loyal than ever to the iconic collections, while enriching them with a powerful modern touch bearing the hallmark of innovation and technical breakthroughs.