The Automatic Bobble Shaker is 2 inches high and 4 inches wide and uses an ingenious sound activated sensing system to set your bobbleheads in motion with a gentle clap or mid-level ambient noise. The wobbling stops automatically after about two minutes, ready for another handclap or serendipitous sound. The Automatic Bobble Shaker can also be set to operate continuously; two AA alkaline batteries (not included) allow more than 72 hours of continuous