Jacques Cousteau and Pierre-Antoine was released in 1954. During the 1940s, Cousteau is credited with improving the aqua-lung design which gave birth to the open-circuit scuba technology used today. According to his first book, "" (1953), Cousteau started diving with Fernez goggles in 1936, and in 1939 used the self-contained underwater breathing apparatus invented in 1926 by Commander Yves le Prieur. Cousteau was not satisfied with the length of time he could spend underwater with the Le Prieur apparatus so he improved it to extend underwater duration by adding a demand regulator, invented in 1942 by Émile Gagnan. In 1943 Cousteau tried
History of underwater diving regulator was adapted to diving, and the new Cousteau-Gagnan patent was registered some weeks later in 1943. Air Liquide started selling the Cousteau-Gagnan regulator commercially as of 1946 under the name of "scaphandre Cousteau-Gagnan" or CG45 ("C" for Cousteau, "G" for Gagnan and 45 for the 1945 patent). The same year Air Liquide created a division called "La Spirotechnique", to develop and sell regulators and other diving equipment. To sell his regulator in English-speaking countries Cousteau registered the Aqua-Lung trademark, which was first licensed to the U.S. Divers company (the American division of Air Liquide) and later sold with La