'The Wave' tide clock by Downeaster is a unique concept in tide clocks! The center disc turns to simulate the ocean's tides at a rate equivalent to one lunar second per pulse. The tide clock's cycle is geared to Atlantic Coast tides (approximately two High and two Low tides per day). Highly polished and lacquered 6" brass case. A must have for all fishermen, boaters, and nature lovers! Made in USA. Operates on a single AA battery.