My first regulator was a Healthways Scuba double hose regulator, and I have one that still works. You can see it below on a twin tank system. The Scuba Star regulator was my first single hose regulator; I have both versions, the upstream and the downstream valve second stages.
I also have a set of Duck Feet fins that still works well, and are probably older than many divers today. The U.S. Divers Company Professional Fins are probably from the same era, a competitor to the Duck Feet fins.
My Champion Deluxe mask by U.S. Divers Company is dated back into the 1960s, and still works too. It is in the middle row, second from the right in my collection of masks.
For those who think these old regulators are dangerous, breathe hard, and should not be dived, I have one regulator in my collection that no “modern” regulator can beat, the Scubapro Pilot regulator. And yes, it still works. I had to go through it, and replace several O-rings, and learn more about it. This unique regulator is mainly sealed with O-rings, and does work on the pilot valve principle. You need to be careful in setting it up, as it has a Venturi that can be set too high for comfort.
SeaRat