This pendulum movement runs on one AA battery. You can choose from shaft lengths. All pendulums consist of a 16" adjustable pendulum with a 2 3/4" bob. You can easily trim the pendulum rod to any length under 16". These movements include and hour, minute and second hand. All models have a 5/16" shaft diameter so a 3/8" mounting hole is the correct size to drill in your case. Dimensions: 2 1/4" x 4 1/4" x 5/8" Shaft Length: 7/16" (for dials up to 3/8")