Heavy Duty Clock Pendulum Drive Mechanism Run Up To A 42" Grandfather Size Lyre Pendulum With A 10-1/2" Bob! Saves Money By Allowing Any Regular Small Battery Movement To Run The Time Freeing You From Having To Buy Expensive Mechanical Pendulum Movements. Case Size Of This Movement Is 8-3/8" High x 3" Wide x 2-1/8" Deep. Requires 1 'D' Battery, Not Included.