H400 Diving Tank 1.0L Diving Tank Holder 15-20 Minutes Breath Portable Tank with On/Off Valve Pony Bottle for Exploration Fun/Emergency

There were no instructions and lots of spare seals

Be careful when you buy this. The hose to tank connector leaks. The seal is an exposed o ring. It's only air tight when the o ring is squeezed at the perfect point. If the hose screwed in too tight, the o ring deforms and leak. If wiggled the hose, it will leak. I plan to use this as alt during scuba diving, and mount at my back. So it can totally leak all the air during a dive.

The mini scuba tank is made for short underwater dives and emergencies. The constant pressure breathing valve works flawlessly and feels very safe compared to older designs. The 6061 aviation aluminum build is solid yet lightweight and I love that the tank can be separated from the valve for easy air travel. It truly delivers close to 20 minutes of underwater breathing (depending on depth and breathing rate) which is perfect for boat maintenance underwater photography, or pool training. The multiple filling options are very convenient and the included scuba adapter makes refilling quick and easy. Overall this is a reliable portable and well-designed scuba tank an excellent choice for recreational divers and explorers.

Pretty neat back up air tank, comes with a pump and filter to refill.

The tank is lightweight, easy to carry, and provides a solid 15–20 minutes of air. Great for quick underwater exploration or backup use. Feels well-built and reliable.