This is the clock modeled after those used by the U.S. Navy to keep time on World War II vessels. Made by Chelsea Clock, crafters of the original maritime timepieces for the U.S. Navy since 1900, the clock uses precise quartz movement and displays the time in 12- and 24-hour formats with a sweeping second hand. Hand-assembled by master clockmakers and tested for 14 days, the clock has a phenolic case that is heat-resistant and withstands high-impacts, preventing corrosion or cracking. The bezel has a locking brass bolt and a rubber O-ring that keep moisture and dirt out to ensure reliable outdoor timekeeping in the face of inclement weather and drastic changes in temperature. The shatterproof polycarbonate lens protects the 5 1/2" dial and the hinged bezel opens to allow simple time adjustments and replacement of the one included AA battery. The included mounting hardware enables easy wall-mounting indoors, outdoors, or on a boat. 6 3/4" Diam. x 2 1/2" D. (1 1/2 lbs.)