This is a brand new Rotating Pendulum Drive Movement for Anniversary clocks. It DOES NOT regulate or run the timekeeping. It has an off-centered positioned shaft for the pendulum (please see pictures and make sure this will work under the base of your clock) Some clocks require a movement with a centered post only The movement mounts under the clock base with the shaft protruding through the base hole. The movement case size is 2-1/8"W x 2-1/4"H x 5/8"Deep. The pendulum is 2-5/8" high and 2-3/4" in diameter. The total assembled height is 3-1/2". Requires 1 'AA' battery (not included). This movement will only run a light weight plastic pendulum like the one we include. We cannot guarantee it will run a heavier metal or glass pendulum.