Proberos® Breathing Trainer, Portable Muscle Trainer, Exercise Trainer with Resistance Adjustable, Easy to Clean and Use, Improve Strength and Endurance

It's good. Does what it says, I can actually feel the improvement in my chest and throat after using this. Very easy to use, just grip it between the teeth. The instructions say to breathe in and out through the device, I prefer to breathe in from nose and only exhale through the device. I'm ordering 2 more for my wife and mother.

Only one with both expiration and inspirations controlls useful

Deducted 1 marks as the packaging could have been better.As per the effectiveness is concerned, as I never used such products, can tell after a month of use . Overall I think it should work as the breathing gets heavy while using and you can feel the lungs really working. A thumbs up

The resistance is same on all the levels. The packaging looks very suspicious.

Great product! good packaging! this will get your lungs in shape. you can adjust it to make the "workout" easier or harder.