I was given one after i had a chest tube operation-a broken rib had punctured my lung-i used it regularly and when my lung was stronger i forgot about it-years later i developed copd moderate to severe -now i have emphysema-i dragged the blue plastic pipe with its ball and dial from the bookcase and started to use it again-it really helps when i just need to clear my lungs and dont want to use my nebulizer or inhaler