Alpina 107 (Gruen 107, 1077)

Alpina Gruen Gilde 1929-1937 *) Flume lists the frequencies 18000 and 20160 A/h, but in Gruen catalogs an according remark is missing. bimetallic screw balance, Breguet hairspring signature often or always Gruen 106 (example movement out of Alpina watch) differences not known between 106, 107 probably designations for different base-plate shapes, round corners (Fig.1, 2) or octogonal