Tide Timers are a perfect gift for anyone with a coastal home or boat, fishermen, swimmers, surfers and beachcombers. They offer a simple, reliable way to keep track of the tides! The tides operate on moon time, where each tidal day has 24 hours and 50 1/2 minutes, so high and low tides do not occur at the same hour each day. The Tide Timer's red ball hand conveniently shows -at a glance - how many hours until the next High or Low tide in your area. Tide Timers are much easier to read than printed tide tables, and come in a variety of styles to compliment any decor. Tide Timers are recommended for use on both Coasts of the United States and Canada. On the Atlantic they never need adjustment. On the Pacific, including Hawaii, they can be calibrated to different coastal locations using our proprietary setting tables. Tide Clocks do not operate in the Gulf of Mexico. Schelling Corp has been making and guaranteeing their Tide Timers since 1971.