Lung T-500 (small compressed air dive tank) is dangerous

Any handheld, hand-pumped air supply is dangerous without training, don’t buy them

Joshua Dance
7 min readJun 30, 2023

Instagram is showing a lot of ads for ‘hand-pumped scuba tanks’.

There are a bunch of different brand names, all selling the same product. (Maybe from the same outsourced manufacturer.) These brands have names like:

  • Scopel
  • Scorkl
  • Smaco
  • Lung T
  • MiniDive

Whatever the brand name, don’t buy one, they are dangerous.

I am Scuba certified and have dove in multiple countries. Let’s talk about why these handheld mini scuba tanks are dangerous.

7 Reasons the Lungtank (and similar hand held compressed air bottles) is dangerous

1. Compressed air with no training is dangerous.

Compressed air is incredibly powerful. That power is what allows you to breathe underwater when the pressure of the water is pushing on your lungs.

But anything incredibly powerful is dangerous. There is a reason why Scuba shops won’t rent you gear or take you diving if you are not Scuba certified.

One example of the dangers of powerful compressed air, if you hold your breath ascending from deep to shallow, it can literally burst your lungs.

There is a demo where they fill a balloon underwater, then take it up. The air in the balloon expands until it bursts. That is exactly what your lungs would do. This would kill you.

When you get certified to use and breathe compressed air, you learn about the dangers, and how to avoid them. The intended audience for these handheld bottles does not have the correct training.

2. ‘Mouth held’ means you can easily lose your air supply

Scuba mouthpieces (called regulators) are attached to a hose, which is attached to a tank, that is strapped securely on your back. You can’t truly lose it.

However, your mouthpiece can be removed from your mouth accidentally. So in training, you are literally drilled on recovering lost regulators. Multiple times you have to demonstrate the skill where you have to take the regulator out of your mouth, let go of it completely, then recover it and breathe again.

A little tank that is only held in by the strength of your mouth is a recipe for disaster.

If you lose your air and panic it can be awful, and deadly.

And it is super easy to lose a mouthpiece.

  • You are swimming along, and someone in front of you accidentally kicks it out.
  • You yourself reaching above your head to grab a shell or something and you clip it, hitting it out of your mouth.
  • An octopus deciding it wants your regulator (seriously happened)

Even the little tanks with a chest lanyard etc are dangerous because you haven’t trained to recover them.

3. Can’t read the pressure gauge easily

In most of these little tanks, you can’t read the pressure gauge without taking it out of your mouth. Not being able to read the gauge means you can run out of air.

Running out of air suddenly is scary and dangerous.

I nearly ran out of air on a dive once. I wasn’t paying super close attention. I was following a very experienced diver. We were about 35–50 feet deep. Luckily he wanted to go check something out but decided to check air supply first. I looked at my air supply and couldn’t figure out what had happened. Where was the needle?

… oh the needle was near the bottom of the gauge. Near empty. I showed my dive buddy, and we surfaced safely. Because we were following our training, luckily I had a dive buddy, and could have used his spare air if needed but it was scary.

When diving, you are responsible for constantly checking your air supply. Checking your air is easy to do, as the gauge is on a hose. You simply grab your gauge because it is attached you know where it is, and read it.

If checking your air is hard to do like it is with these mouth held small bottles (hold breath, pull out mouth piece, read gauge, put it back it) you are going to do it less.

Running out of air underwater is dangerous. A compressed air system with a hard to read air gauge is dangerous.

4. No backup mouthpiece

Scuba gear always includes a backup regulator. If yours breaks, you can use your 2nd.

If a friend runs out of air, they can breath off yours.

These mini tanks have no backup.

5. No depth gauge or hard-to-read depth gauge

Diving is all about depth. How deep you can go, how long you can stay, how much air you use, how bouyant you are, EVERYTHING depends on how deep you are.

To know how deep you are, you need a depth or pressure gauge.

These don’t have them, or they are hard to read.

That means you will have no way of knowing your depth. And when you are underwater, you can’t just ‘tell’. If you can’t the bottom, if there are strong currents, if you get distracted looking at fish, all of these make it difficult to control your depth.

And the worst part is in the safety manuals of these products, they say

6. Don’t recommend you go below 3 meters or 9.5 feet.

They talk on the site about exploring etc but in their manual, they say only use it to 9 feet.

No one will do that.

For one, how will you know how deep you are because there is no depth gauge.

Second, even experienced divers have trouble maintaining certain depths.

Three, a lot of interesting stuff is lower than 9 feet. So users are going to dive, see something interesting, keep going lower and lower until they are 55 feet down and not even realize they are that deep.

7. Compressed air compresses pollutants

Scuba tanks are filled with filtered air so it is clean and free of issues. This hand-pumped tank is not filled with filtered air, it just compresses normal air.

Compressed pollutants in your air can do very bad things. For example, if you are pumping it up in the parking lot at the beach, there can be more carbon monoxide than normal from car pollution. The compression increases amount of pollution. Carbon monoxide can replace the oxygen in your blood with significant and deadly issues.

You only breathe filtered pressurized air. These systems don’t filter it.

But what about SpareAir and Pony Bottles?

Some will point out that these Instagram compressed air tanks are very similar to backup air systems divers use.

Sold to divers. With training.

And this is correct, but notice the keywords

backup air systems divers use”

Companies like and others sell and market these as backups. Not primary. And they are sold to divers who have the training to use them safely.

Even among Scuba divers, these tanks are

Don’t dive with small pressurized tanks of air

Diving is great and fun. But diving can be dangerous and you need training and equipment for it. If you have training and follow the rules, scuba diving is about as safe as driving a car. But you need the training.

To state it again. Compressed air is powerful. Compressed air is dangerous. Breathing compressed air requires training and proper equipment.

These hand-held portable air tanks are not proper equipment. And most users will not have the required training. Do not buy them. (unless you are Scuba certified)

Want a second opinion?

Dive Magazine wrote an article about why these are dangerous back in 2017 when they were all over Kickstarter.

This Australian YouTuber talks about the same points, and includes others like the fact that pumping up the small tank will take 20 to 45 minutes or hard work pumping, and your air will last half as long at 30 ft, etc.

This YouTuber actually timed himself using one of the tanks in a shallow pool and only go around 3–5 minutes of air.

This international Dive Magazine brings up the same points:



Joshua Dance

Code, design, cook. Make stuff. Cookies. @BYU grad.