 Michelin cylinders contained three litres of air compressed to supplied by Michelin to garages without air compressors for inflation of car tires.Le Prieur approached Fernez, who cooperated to modify his equipment to Le Prieur's idea, and on 6 August 1926 the "Fernez-Le Prieur" diving apparatus was demonstrated at the swimming pool of Tourelles in Paris.The unit consisted of a cylinder of compressed air carried on the back of the diver, connected to a pressure regulator designed by Le Prieur adjusted manually by the diver, with two gauges, one for tank pressure and one for output (supply) pressure.