Type XXI 3817 is a pilot's chronograph from Breguet.

In addition to the classic line, the Breguet brand has also long cultivated the type of pilot's watch. This is because Louis Charles Breguet, great-great-grandson of Abraham-Louis Breguet, was involved in the construction of aircraft and founded a well-known aviation company. The Breguet watch company developed chronograph mechanisms fitted on cockpit instrument panels and began producing pilot’s watches. For example, 1935 saw the development of the first wrist chronographs. Twenty years later, Breguet began producing the Type XX model at the request of the French Army. The popular chronograph was part of the French Army's air force and naval aviators' equipment until the early 1980s.

The Type XXI model was presented at Baselworld 2016. The vintage look recalls the history and origins of the Type XX series, while the distinctive technology firmly anchors this timepiece in the 21st century. Chronograph Type XXI 3817 features a calfskin strap and a slate-colored dial in the style of the time, which is further enhanced by a steel case. Finely fluted on both sides, the watch is water resistant up to 100 meters thanks to a screw-down crown.

The self-winding mechanical movement has a flyback function, which has been a feature of Type XX chronographs since 1954. The chronograph minutes counter is located in the centre, along with its seconds counterpart. The functions of the Type XXI 3817 model also include a 12-hour counter and a date display at 6 o’clock. A day/night indicator and small seconds, respectively positioned at 3 and 9 o’clock, complete the functions.