OBTANIM Tornado in A Bottle, 8 Pcs Tornado Tube Bottle Connector Cyclone Tube for Scientific Experiment (Random Color)

Work as advertised. My daughter loved her tornado in a bottle. As other reviewers have stated, make sure you remove the plastic ring from the bottle neck before using these. If you don’t they won’t screw on tight enough and will leak.

Would probably have better luck just duck taping 2 soda bottles together! These don't even pretend to twist onto the bottles. Way too big.UPDATE! Figured out that you have to remove the plastic ring from the soda bottles! However, 2 liter bottles are still a little too heavy and will sometimes come apart. I recommend using 20 oz bottles instead!

I was somewhat surprised to find that the adaptors would not screw onto any standard plastic soda bottle until I cut off the plastic ring left on the bottle neck when breaking the seal on the cap. That ring keeps the bottle threads from being able to engage the threads inside the adaptor. Once removed, they screw on adequately. The neck of these adaptors is really just a bit too long but you can make them work. I plan to use these on backpacking trips to filter cloudy water through charcoal after boiling it. Boiling kills biological hazards in the water, but running it through charcoal removes other dangers such as pesticides, herbicides and heavy metals and makes the water taste so much better. These adaptors allow me to cut the bottom off a plastic soda bottle, jam a cloth in the neck and fill the upside down bottle with crushed charcoal. Screwed to another bottle, I pour the boiled and cooled water through the charcoal and the clean water goes right into the lower bottle. While I don't need eight of them, the price was very close to the price of a single adaptor also sold on Amazon. I may lose one and need a replacement or give the extras away. I can't speak for science, but for water treatment, these work well after removing the plastic ring on the bottle neck.

As other reviewers have mentioned, you do need to cut off the plastic ring from the bottleneck in order for these to fit properly. Once I cut off the plastic ring, the piece went on just fine but it doesn't fit tightly and there was some minor leaking.

I took the rings off the bottles to ensure a good fit, but these valves just don't fit properly. The bottles kept popping off the valve--with the water dumping out--making a large, slippery mess. Money wasted for this customer, unfortunately.

Works as expected. We used empty 2 liter plastic bottles with the plastic rings (from the caps) removed. Didn’t have any lamp oil in the house so we just used food coloring and it still looked cool. The kids were amazed!

The whole seems to be a bit too small and it was hard to get the tornado going. I also had some leaking issues but the kids were only using outside so it wasn’t an issue.

The media could not be loaded.  Got a pack for my daughter to take into class, because they're learning about weather and tornadoes! I had one of these when I was little. Try to find bottles with sturdy plastic, so many nowadays are really flimsy, they still work but I'm afraid they're going to crack and leak. You have to take the plastic ring off the bottle, the one that is attached to the lid. We added glitter to ours. I kept a couple and gave the rest to her teacher!