Here is my update from my original article, dated 12/25/2018. It works! “After one month of using this simple device, my vital capacity (amount of forces inhalation) increased from 2,500 ml to 4,000 ml. Read this first- Would you like to increase your air intake? So would I. – Trumpet Blog (thetrumpetblog.com) Voldyne 5000 how does it work The Voldyne 5000 Spirometer Volumetric Exerciser from Hudson RCI is a spirometer used for breathing therapy. It has a clever low-work-of-breathing filter and a high volume measurement. A built-in grip and a compact ergonomic design are included in this spirometer. The Voldyne…