Okay, this is awesome! As an allergy/LPR/GERD potential asthma/COPD sufferer I watched videos of this on YouTube and thought If It sucks I can return it. I saw pulmonologists say they give these to their patients. The very first time I used it I feel the weirdest and coolest vibration in my chest, not even feeling any congestion, coughed up a chunk of phlegm. You can REALLY feel when you’re at the right angle by the rattle in your chest, instantly followed by phlegm production. Money well spent!