This clock has a second hand to ensure proper movement, plus a tide indicator hand which is calibrated to the Atlantic lunar tide cycle. (Note: The clock will work for other tidal bodies of water but will need to be re-set more frequently.) It uses a AA battery (included).Dial: 3-1/2". Base: 4-1/2". Depth: 1-1/4".Wt. 5.2 oz.