Genuine Montrelo Loi Military Watch AN5740 Master Navigation Watch Quartz Men's Watch AN5740-24H-BK M.R.M.W. A navigation pocket watch used by the US Army and Navy during World War II. The model name is "AN5740". "A" stands for ARMY, and "N" stands for NAVY. We attached a specialized case to this pocket watch to create a watch that can be enjoyed as both a wristwatch and a pocket watch. The hours are written in 1-24 hour format on the inside, and the seconds are written on the outside in 5-second increments. G.C.T written on the text version is (abbreviation for Greenwich Civil Time). The large font version makes it easy to read the time even on a 24-hour clock. It has been resized to make it easier to use as a wristwatch.