Waltham 650

1934-1942, 531500 bimetallic screw balance, Breguet hairspring safety barrel (Fig.3): Ratched wheel and barrel are coupled to the barrel staff by squares; the first wheel with joint spring core is running on the long middle section of the staff. This design cares for low bearing pressure, and reliably prevents damaging of teeth if a breaking spring strikes into the barrel. differences not known between 6.5" , 650 Grades: 659: 9 jewels 665: 15 jewels 667: 17 jewels