Right now, an Indiegogo campaign for a device that its makers claim is "the future of underwater breathing" is raking in cash — more than $600,000 at the time of this post, $100,000 of which poured in over just 24 hours.

It's easy to see the appeal of the handheld device, called the "Triton." Diving equipment is heavy and complicated. Meanwhile, the Triton looks seductively simple and the campaign says it "allows you to breathe underwater."

But despite the slick crowdfunding campaign, there's no real evidence that this device actually works, multiple experts told Tech Insider.

One of them is Neal Pollock, a research associate at the Center for Hyperbaric Medicine and Environmental Physiology at Duke University Medical Center, and the research director for the Divers Alert Network — a non-profit organization that helps divers in medical emergencies and promotes dive safety.

"In concept it sounds very good and it's very exciting," Pollock tells Tech Insider, but "I would not encourage anyone pulling out a wallet."

For the makers of Triton to prove they've invented a device that can actually do what they say it can, Pollock and other experts want to see more evidence; the crowdfunding campaign and Triton website simply don't provide enough to go on.

Regardless, Pollock notes the technological challenges involved in creating a device like Triton are so vast that "it's not realistic, it's science fiction" — more in the realm of James Bond in "Thunderball" or Jedi knights in "Star Wars: Episode I."

Why making a device like this is such a challenge

The Triton campaign claims its device filters water through tiny holes in the "gills" that extract oxygen. A tiny battery-powered "micro compressor" then stores the oxygen in a miniature storage tank, from which a swimmer can "breathe freely."

For an artificial underwater breathing device that'd work like "underwater gills," Pollock says you have to solve three major issues.

First, your device has to actually extract enough oxygen from water to fulfill your biological needs. In theory, a device could pull enough oxygen from water to do this, but it would have to be incredibly efficient and it would need to filter enough water to actually collect all that oxygen.

In 2014, when the Triton device was first proposed, marine biologist and diver Alistair Dove weighed in on this problem at Deep Sea News.

Dove notes that even if a device is 100% efficient at pulling oxygen from water, you'd still need to force enough water through a pump to collect all the oxygen required to breathe normally — upwards of five liters every 15 seconds. He calculated doing so would require a pump bigger than the Triton itself. And since there's apparently no water pump on the device, it's unlikely enough water could naturally pass through it while swimming to provide the oxygen our bodies need.

Second, even if you'd solved the oxygen extraction issue, you'd then need to get that gas into a storage chamber. The Triton campaign says the device has a "very powerful modified micro compressor" (emphasis theirs) to store it.

Compressing oxygen requires a lot of energy, and you'd have to store enough of the gas to actually breathe underwater. Also, your storage vessel needs to be strong enough to withstand the incredibly high pressures required to store an adequate volume in such a small container.

Triton essentially claims it has the technology to do this in the palm of your hand — for example, check out the size of the storage tank in the Triton schematic (labeled in blue as "Air Tank").

"[T]heir battery system would have to be orders of magnitude more efficient than anything on the market," deep-sea ecologist Andrew David Thaler told Tech Insider in an email. "At which point you have to wonder why you'd wrap that up in a gimmicky set of gills rather than selling the battery technology. It'd be like cracking cold fusion, but only using it to power a novelty clown lamp."

Finally, even if you could extract the oxygen from the water and had the power and technology to store it, it's still not enough. Divers don't just breathe freely from closed-circuit storage tanks; you need a system that provides you with just enough oxygen, and no more than that.

"You have to deliver enough for physiological needs but not so much that you would create a toxic environment," something that would become more and more of an issue if you went deeper and the gas was more compressed, explains Pollock.

Closed-circuit rebreather technology that provides all the oxygen you need to breathe does exist — it's what divers use when going deep — but those systems carefully meter out oxygen and rely on other gases (like helium or nitrogen) to help make up the difference in the total volume breathed into your lungs.

All of this technology may look familiar: It's a full scuba setup.

"Each one [of those issues] individually is almost insurmountable with a unit that small," says Pollock. "Putting the three of them together, I just don't see it in our immediate future."

To be clear, Pollock and others are not saying a device like Triton could never happen. But when it does happen, its inventors will need to show that they've made something that works.

The team behind Triton's Indiegogo campaign — including designer Jeabyun Yeon, the campaign's leader — did not respond to Tech Insider's multiple requests for comment by phone and email, which included questions about how it had solved these problems.

On the Indiegogo campaign page, however, Triton co-founder Saeed Khademi has responded to several commenters who posted Alistair Dove's Deep Sea News post (you can only comment if you've donated to the campaign).

Khademi, describes himself as a Swedish entrepreneur, told one crowdfunder: "Yes I have a very easy explanation for that, first of all that article is from Jan 2014 that more then 2 years ago, and second the technology withTriton is not the same, because we have not yet released the full technology data of Triton due to our patents, and what the article is saying is a theory we had when we first just had designed Triton, we have achieved a lot since then :)."

None of Khademi's responses explain how they'd solve any of the problems that scientists have pointed out with the device.

No reason to believe this works

As a diver, I can tell you that breathing underwater is one of the most magical experiences possible. I want this to work. But I'd want to see proof that it does before actually using it to breathe underwater — or before paying $299 for one.

Thaler, who evaluates ocean-based crowdfunding campaigns on the website Southern Fried Science, points out there a number of red flags.

A big one, Thaler told Tech Insider, is that the device shown in the campaign appears identical to the concept art created two years ago by a Yeon, who has no identifiable background in physics or engineering. (The other two members of the team include an entrepreneur and a marketer, and the campaign says they'd like to hire a "technician in marine technology" sometime in the fall — right before they're supposed to ship the device, in December 2016.)

"To have pitched a piece of concept art and in two years made no substantive changes suggests to me that it is very unlikely they have a working device," Thaler writes. It's also worth pointing out that Indiegogo does not require a working prototype.

In the videos the Triton team has posted "demonstrating the technology," there's also no shot of anyone underwater that lasts longer than a minute. Tech Insider has asked for footage that would show someone using the device for a longer period of time, which would go a long way towards showing that something functional has been created, but we haven't yet heard back.

"I think there's very good reason to be skeptical," says Pollock.

Again, we love this idea — it's looked fun in movies for decades. But until there's proof that someone has cleared the technological hurdles involved, holding onto your money is a sound idea.

Story by Kevin Loria. Video by Darren Weaver.