The day of the week and month are displayed side by side at the 12 o'clock position, and the crescent-shaped center hand displays the date, creating a very unique style. In addition to an aviation-use rotating slide rule and a tachymeter scale, the sub-dial at the 9 o'clock position is equipped with a 24-hour counter.

The first "Chronomat" was released in 1942 and was the world's first chronograph with a rotating slide rule. The Montbrillant model, which was released in 1995, inherited its design. The prototype of the Montbrillant Datra is the triple calendar chronograph "Datra" manufactured in the 1940s.

The Montbrillant Datra, a revival of the famous 1940s model, is now available with two dials: black and silver. The red "decimal meter" in the center of the dial is an accent.