Walk the beach or watch the tide coming in? It's easier to decide what to do if you know whether the tide is in or out. Blue "Tide Hand" shows high, low, and half tides. It cleverly runs on a 25 hour day, the moon's day cycle. The moon governs the earth's tides with its gravity pull. It's easy to adjust to your location and instructions are included. Solid brass case, quartz movement.