I have suffered from copd/emphasema for many years and recently had two bad colds resulting inn my breathing reduced to 200 on my meter, unable to get suitable help from the hospital or doctors I bought myself a nebulizer and a RC CORNET to help me improve my breathing and to get rid of the build up of sputum I have difficulty in coughing up. WOW what a difference the RC CORNET has made. £ times a day for 5 mins and although it was giving me excessive chest pain at first after a couple of months I find I am breathing completely different. If you suffer like me I would recommend you get a RC CORNET and give it a go. I still use every day despite my health has improved and back to normal.