#8/3 American made double end brass key, sized on the American scale. This key fits all Jahresuhrenfabrik (JUF) disc pendulum clocks. The large end (4.0mm) is used to wind the movement, and the small end (2.0mm) is used to turn the regulating screw on the disc pendulum.

Measure your winding arbor, or ask us for help to determine the right key size for your anniversary clock.