Weems & Plath's Endurance Collection combines precision instrumentation with classic design. The result is an instrument you would be equally proud to display or give. The Tide Clock uses a highly accurate quartz movement with a lifetime warranty that controls both the time hands and the tide indicator. One of the more unique features of the Endurance line is the slide-on mounting system that makes time changes and tide adjustments a breeze. Measuring 6" at the base and 1 5/8" thick the brass case is guaranteed never to tarnish. The beveled glass crystal is 4 7/8" in diameter. This tide clock is optimized for use on the east coast of North America. AA Battery included.