An antique West German Kern Anniversary gold tone metal mantel clock with a clear glass dome. A torsion pendulum clock, more commonly known as an anniversary clock or 400 day clock, is a mechanical clock that keeps time with a mechanism called a torsion pendulum. This is a weighted disk or wheel, often a decorative wheel with 3 or 4 chrome balls on ornate spokes, suspended by a thin wire or ribbon called a torsion spring (also known as suspension spring). The torsion pendulum rotates about the vertical axis of the wire, twisting it, instead of swinging like an ordinary pendulum. A cream tone enameled dial with gold tone numerals and dials. Marked, Kern, on the front and with manufacturer stamp on the back. Circa: late 19th century. Antique and Vintage Pendulum Mantel Clock, Home Decor, and Collectibles.