Combination quartz and tide clock movement which averages the Atlantic lunar tide cycle. The tide sector is calibrated for the east coast of the United States. Uses a AA battery. (Note: The clock will work for other tidal bodies of water but will need to be re-set more frequently.)Dial: 4". Base: 5-1/2". Depth: 2-3/4".Wt. 3 lbs. 3 oz.