EXCYINSIFitness Exercise Trainer | Improve Fitness | Adjustable Exercise Trainer for Fitness Training Easy to Use for Normal Care & Exercise

I use it quite frequently and helps with my lungs.

Easy to use and clean. Small compact design so it fits in my gym bag nicely. Been using as a training tool to increase lung capacity and it has been highly effective.

Simple and easy to use. After a few days I could feel the effects. Felt like I had done sit-ups. Don’t know if it does anything to improve overall breathing performance. But I will continue to use it and will update when I get an answer

This will definitely help you breath better

If you can enlarge and read the instructions they are somewhat humorous and an obviously poor translation from a foreign language. They tell you to "engrave the word 'top' on the bottom of the mouthpiece," refers to it as a cigarette holder, and tells you to "breathe normally until you resume breathing." HA! The one I received is stamped Expand-A-Lung on the adjustment knob but the package wasn't actually sealed so unsure if it is authentic or ??? I washed it thoroughly before using of course and it seems to function as it should (very basic) and only time will tell if it actually lowers blood pressure or increases lung/heart fitness. Perhaps it is my imagination but after using it and cleaning it several times, the adjustment no longer seems to provide adequate restriction of airflow even when cranked as tight as it will go.