The Bettlach 8370-67 watch movement is an open face calibre movement produced by IWC during the period of 1888-1904. It had a production quantity of approximately 19,650 units during this time. The movement features a bimetallic screw balance with four adjustment screws, a Breguet hairspring, and a barrel with Geneva stopwork. It includes functions such as stem winding and pin setting, as well as a sub-second display.