In 1933, Léon's grandson Willy Breitling filed two patents for a chronograph mechanism with two pushers (Swiss patents No 172129 and 175564) for stopping and resetting to zero. 1934 - Wrist chronograph with two pushbuttons for measuring several successive short intervals (Breitling patents). (1) 1) https://www.hautehorlogerie.org/en/brands/history/h/breitling/ 2) http://orologi.forumfree.it/?t=73089153