Vintage Cousteau Gagnan 'Aqua Lung' double hose scuba regulator, $20.

Scuba diving equipment - from regulators, to masks, to computers, to weights, to buoyancy compensating vests - is expensive stuff that your bidders will be looking for. This means that the more of this stuff you know about, and are able to identify, the more money you stand to make!

What many people never learn is that collecting vintage diving equipment like masks, fins, spear guns, gauges, tanks, regulators and anything else related to diving, has become increasingly popular in recent years. So it will also pay you to familiarize yourself with the old dive equipment like this Cousteau Gagnan Aqua Lung piece!

Let's face it, there are collectibles, and there are collectibles. There's the fluffy, hyped, misleading foolishness that everyone (that is, except the real eBay buyers with the real money to spend) seems to think is worth big money. And then, there are the 'fringe collectibles,' as I call them, that are so damned unusual that not only are they really uncommon, but few people - except those who actually looking for them - even know what they are or what they're worth.

As you may already know, the acronym SCUBA stands for Self Contained Underwater Breathing Apparatus. Although the scuba diver normally wears all sorts of equipment to make diving possible, the breathing part of the apparatus is understandably the most important part of the system, and has presented the most challenges to the people who were determined to make scuba diving reliable, practical and safe.

Back in the early 1940's, Jacques Cousteau was working to develop a system for breathing underwater, and realized that he'd need some sort of a regulator valve that would convert the very high pressures from a tank of compressed air, to a regulated source of on-demand air that a diver could breathe. Cousteau teamed up with a guy named Emile Gagnan, who had developed a valve he'd originally designed, which was intended to allow a car to run on a bag of coal gas strapped atop its roof. I don't think there's any question that Gagnan saw the future of both of these applications.

The modern scuba outfit (not the Cousteau-Gagnan unit in our example here) starts with an air tank pressurized to around 3000 - 3400 p.s.i. (pounds per square inch of pressure.) The first stage regulator, which screws right onto the top of the air tank, reduces the tank's pressure to around 140 p.s.i., where it's then routed via two small hoses to a pair of second stage regulators. One regulator fits right at the diver's mouth, and the other is an emergency spare that's kept aside.

One function of the second stage regulator is to convert the 140 p.s.i. air to an 'on-demand' air supply, meaning that all the diver has to do is inhale to start the flow of air, and stop inhaling to stop the flow. The other function of the second stage is to maintain this fine balance of effortless breathing regardless of the diver's depth. This may seem unimportant until you consider that a diver 50 or 60 feet down will require air at a much higher pressure than he will at ten feet of depth, so the regulator has to compensate for any depths the diver will be operating in. As the diver exhales, the air escapes from the sides of the regulator, right outside his mouth.

The vintage dual-hose style regulator in our example here was in use from the late 1940's until as late as the early 1970's. In the days when this system was popular, air tanks were generally pressurized to around 1800 - 2250 p.s.i., and the regulator (the round silver thing in the photo that the hoses connect to) was secured directly to the tank. Unlike the modern two-stage regulator system, where the first and second stages are located separately, this older style regulator came in both single and double stage varieties, which was sometimes indicated right on the regulator itself. But whether one stage or two, the whole regulator was contained in one unit that clamped right onto the air tank. Using the dual hose system, the diver inhales air through one hose, and as he exhales, the air passes out through the other hose and back to the regulator, where it exits behind the diver through a one-way valve in the regulator itself.

As for the advantages and disadvantages of each of these systems, you could waste lots of time and effort needlessly debating them. I have heard that the double hose system is popular with some underwater photographers because the bubbles exit behind the diver instead of right in front of his face mask, leaving less chance of disrupting the picture. It's popular with some arctic divers because the larger hoses are less susceptible to icing up in very low temperatures, for whatever that's worth. All I can say is that if the double hose system were the superior of the two, it would be the prominent one in use today.

So, why bother with explaining this old stuff? Well, there are two good reasons I can think of. As I constantly repeat here at Auctionbandits, it seems like I go into unnecessary detail to explain things that don't even seem worth bothering with. But I'm always careful to explain my reasons in the end. Let's take a look at the importance of this unusual gadget.

As unusual and dangerous as it may sound, there are many divers who actually enjoy diving with this weird-looking old diving equipment. And I'm not talking about just regulators, either. These people head out to sea wearing vintage masks, regulators, tanks, wetsuits, fins - the works! Keeping in mind that scuba diving inherently dangerous with even the most modern equipment, these people are extra special fanatics! Considering the risks involved, I assume that all this diving happens only after proper inspecting and any necessary rebuilding of the equipment!

Among both divers and non-divers alike, the collecting of vintage diving equipment has become very hot on eBay, and it's not going away. And I'm not talking about just diving regulators, either. People are snapping up vintage masks, fins, depth gauges, weight belts, spear guns, air tanks, vests, wetsuits, magazines, everything. As you know, when it comes to collecting, some items will always be worth more than others. The rule to keep in mind is that whenever you see something old that's related to diving, you should grab it if you can get it cheap, because chances are that someone out there on eBay will gladly buy it from you.

With such strong interest in this old diving equipment, you simply must be aware that this stuff is out there, as well as why you should look for it. And a little information about one component in this industry's history is a great start. This vintage Cousteau Gagnan regulator sold on eBay to a guy in Australia for $265.

Photo of vintage Cousteau Gagnan regulator