The ETA 2512-1 watch movement, used from 1927 onwards, features a manual wind mechanism. Its frequency, as listed by Flume, is either 18,000 or 20,160 A/h. However, Gruen catalogs do not provide specific details regarding this aspect. The movement incorporates a bimetallic screw balance and a Breguet hairspring. It is commonly or always identified by the signature Gruen 106, with no known differences between the designations 1067 and 1077. The 106 series is likely related to the shape of the base-plate, which may either have round corners or an octagonal shape.