A bit of history about single-hose regulators
A little history on the modern regulator ...
Ted ELDRED (1920 - 2005) is an Australian who was recognized as the first inventor of the 2-stage regulator in the world in 1952.
The development of this technology began in 1949. Ted ELDRED's company, Breathing Appliances Pty Ltd, was located in Melbourne where the first regulators and hookahs of the PORPOISE brand were manufactured.
The performance of PORPOISE regulators was superior to that obtained with Aqualung regulators from Cousteau-Gagnan technology, from 1955. This period corresponded to a phase of great development of the company Breathing Appliance Co, by the submission of numerous prototypes with the Australian navy, which largely surpassed all the attempts made by their competitors, made in a framework of global development. Unfortunately Ted ELDRED ceded his patents to AQUALUNG by the constraint of "commercial intimidation" in 1956.
In this photo, one of the very first versions of the PORPOISE regulator from the early 1950s.
In May 1955 the Marseillais BRONNEC and GAUTIER filed a patent on a two-stage "mouth" regulator, The fabulous Cristal regulator. Immediately, Major Cousteau will sue them, however he will lose the trial.
This did not prevent AQUALUNG from releasing in 1958 its first "mouth" regulator: the AQUAMATIC, marketed worldwide (example: AQUALUNG / US DIVER in the USA, SPIROTECHNIQUE in France, BARAKOUDA in Germany ...)