English: Old-type "twin-hose" aqualung I made the image with CGI. Anthony Appleyard (talk)

Note that the diver in this graphic is standing leaning somewhat forwards. The straight-up position is seen often in films of divers played by actors, who invariably wear mockup non-metal tanks in somewhat the same manner as actors always carry empty suitcases and wear empty camping backpacks. Real divers with real metal tanks weighing 20 kg or more each on their backs, always walk with a characteristically bent-over position.