Just as 19th-century railroads pushed the development of the pocket watch to higher standards of performance, so the wars of the 20th century influenced the development of the wristwatch.
During World War I, Omega made wristwatches for British Royal Flying Corps, as well as for communications troops in the U. Some versions featured tempered-steel grids over the watch face to protect it from shocks.
Breitling was another favorite supplier to British forces.
In 1923, Breitling developed the first chronograph with an independent pushpiece, making start and return-to-zero functions (known as flyback) simpler and more intuitive.
The addition of a second return-to-zero pushpiece improved the wristwatch’s functionality for pilots, which is one of the reasons why the Royal Air Force made Breitling its official supplier in 1936.
Even during World War II, Breitling continued to innovate.
In 1942, the company debuted its Chronomat, the first chronograph wristwatch to be fitted with a circular slide rule on the bezel.
These watches proved popular with the non-military public after the war, and vintage Chronomats are highly collectible today. Hamilton also made watches during World War II (more than 110,000 for the Army alone), but not the A-11.
Other World War II suppliers included Bulova, Elgin, and Waltham, all of whom produced the Type A-11 for the U. One of the rarest Hamilton watches from this period is the R88-W-800.
Only about 15,000 were made—watches for the Navy had a black face, watches for the Marine Corps had a white face.
In addition to A-11s, Elgin made one of the most collectible vintage wristwatches of the World War II era, the Navy Canteen Military Dive Watch.
These watches are distinctive because of their smaller face.