The basic Sea Service pattern was used from the mid-18th century into the early 19th century by the Royal Navy around the globe including during the French & Indian War, American Revolution, War of 1812, and Napoleonic Wars. "TOWER" marked at the tail of the lock, a "crown/GR" royal cipher and "crown/broad arrow" marked at the center of the lock, and "broad arrow/BO" stamped on top of the wrist.