Title: Aqua-Lung
Content:  For the firms named Aqua Lung, see Aqua Lung/La Spirotechnique and Aqua Lung America. For other uses, see Aqualung (disambiguation). Aqua-Lung was the first open-circuit, self-contained underwater breathing apparatus (or "scuba") to achieve worldwide popularity and commercial success. This class of equipment is now commonly referred to as a diving regulator, or demand valve. The Aqua-Lung was invented in France during the winter of 1942–1943 by two Frenchmen: the engineer Émile Gagnan and the Naval Lieutenant (French: "lieutenant de vaisseau") Jacques Cousteau. It allowed Cousteau and Gagnan to film and explore underwater more easily.
Title: Aqua Lung America
Content:  The "Aqua-Lung" regulator was created by Jacques-Yves Cousteau and Émile Gagnan in 1943. In 1946, the company known as La Spirotechnique (now Aqua Lung International) was established by both men together with Jean Delorme, CEO of Air Liquide, as a division of Air Liquide to sell the Aqua-Lung regulators. In the United States, the Aqua-Lung regulator was first sold in the late 1940s by René Sporting Goods, a sporting goods store in Los Angeles, California owned by René Bussoz. He soon obtained a contract with La Spirotechnique to import Aqua-Lung equipment into the United States for sale on the Pacific coast (Spaco, Inc. had the contract for the Atlantic coast). In 1952, Bussoz changed the name of his company to "U.S. Divers Company" and registered the Aqua-Lung trademark in the United States. In 1957, Bussoz sold the company and the trade names to La Spirotechnique. Around 2003, U.S. Divers Company was renamed Aqua Lung America after La Spirotechnique changed its name to Aqua Lung International. The U.S. Divers name is maintained as a trademark for Aqua Lung's line of snorkelling equipment.
Title: Aqua Lung/La Spirotechnique
Content:  Conceived by Jean Bronnec and Raymond Gauthier this regulator was the Cristal, called the Aquamatic for English-speaking countries. The first American branch of La Spirotechnique was U.S. Divers Company, which first sold aqualungs (CG45, Mistral), Aquamatic (Cristal) and other La Spirotechnique regulators in the United States. At some point La Spirotechnique used the word Aqua Lung to change its name, or to use it as an alternate name. Nowadays U.S. Divers Company is known as Aqua Lung America. Aqua Lung/La Spirotechnique sits nowadays in Carros, near Nice and owns its own international branches around the world, like Aqua Lung America. Spirotechnique produced the DC55 passive addition sem-closed rebreather.
Title: Aqua-Lung
Content:  The Aqua-Lung was not the first self contained underwater breathing apparatus, but it was the first to be widely popular. In 1934, René Commeinhes developed a firefighter's breathing apparatus which was adapted for diving by his son Georges in 1937. It was used by the French Navy during the first few years of World War II. The twin-hose Aqua-Lung demand regulator forms the foundation of all modern scuba regulators. A diaphragm is used to control a valve to deliver the breathing gas to the diver on demand, at ambient water pressure. It is not clear who invented the first single hose regulator. The invention was motivated by an effort to bypass Aqua-Lung's patent on the twin-hose regulator, which involved the return of exhaust gas 
Title: Aqua-Lung
Content:  weeks later in 1943. After the war, in 1946, both men founded La Spirotechnique as a division of Air Liquide in order to mass-produce and sell their invention, this time under a new 1945 patent, and known as CG45 ("C" for Cousteau, "G" for Gagnan and "45" for 1945). This same CG45 regulator, produced for more than ten years and commercialized in France as of 1946, was the first to actually be called the "Aqua-Lung". In France, the terms scaphandre autonome ("autonomous diving set"), scaphandre Cousteau-Gagnan ("Cousteau-Gagnan diving set"), or CG45 were meaningful enough for commercialization, but to sell his invention in English-speaking 
Title: Aqua Lung/La Spirotechnique
Content:   Aqua Lung International (formerly La Spirotechnique) is a large and well-known firm which makes scuba and other self-contained breathing apparatus, and other diving equipment. It produced the Aqua-Lung line of regulators, like the CG45 (1945) and the Mistral (1955), among others. Until 2016, the company was a division of Air Liquide since its foundation in 1946. The company was sold to Montagu Private Equity in 2016.
Title: Aqua-Lung
Content:  Aqualung, Aqua-Lung, and Aqua Lung are registered trademarks for scuba diving breathing equipment. That trade name was originally owned in the United States by a company known as U.S. Divers (now Aqua Lung America). The term was in use before the trademark was registered by René Bussoz, who owned a sporting goods store called René Sports in Los Angeles. He obtained a contract with the French firm Air Liquide, the parent company of Aqua Lung/La Spirotechnique, to import the new scuba equipment into the United States for sale on the Pacific coast (SPACO had the contract for the Atlantic coast). Bussoz 
Title: Scuba diving
Content:  German occupation of France, Jacques-Yves Cousteau and Émile Gagnan designed the first successful and safe open-circuit scuba, known as the Aqua-Lung. Their system combined an improved demand regulator with high-pressure air tanks. This was patented in 1945. To sell his regulator in English-speaking countries Cousteau registered the Aqua-Lung trademark, which was first licensed to the U.S. Divers company, and in 1948 to Siebe Gorman of England. Siebe Gorman was allowed to sell in Commonwealth countries, but had difficulty in meeting the demand and the U.S. patent prevented others from making the product. The patent was circumvented by Ted Eldred of Melbourne, 
Title: Aqua-Lung
Content:  An earlier underwater breathing regulator, known as the régulateur, was invented in France in 1860 by Benoît Rouquayrol. He first conceived it as a device to help assist in escaping from flooded mines. The Rouquayrol regulator was adapted to diving in 1864, when Rouquayrol met the lieutenant de vaisseau Auguste Denayrouze. The Rouquayrol-Denayrouze apparatus went into mass production and commercialization on 28 August 1865, when the French Navy Minister ordered the first units. After 1884, several companies and entrepreneurs bought or inherited the patent and produced it until 1965. In 1942, during the German occupation of France, the patent was held by the 
Title: Aqua Lung America
Content:  Aqua Lung America (formerly U.S. Divers Company) is an American company based in Vista, California which makes scuba equipment. The company is a division of Aqua Lung International, which was, for most of its existence, a division of Air Liquide. Aqua Lung International was sold by Air Liquide to Montagu Private Equity by the end of 2016. After U.S. Divers Company was renamed Aqua Lung America, the name U.S. Divers was retained as a trademark for Aqua Lung's line of snorkelling equipment.

Question: who is given credit for inventing the aqua lung?
Answer: Jacques Cousteau.
engineer Émile Gagnan.
Émile Gagnan.