Sue, Bellevue is a New York State Hospital with very strict rules and regulations. Also, NYU Hospital uses Shower Clear in a section of the hospital that does not use hand held units. And, Dr. David Kamelhar from NYU (Look him up) has recommended Shower Clear to his NTM patients.**Dr Kamelhar does not endorse any product. He is recognized throughout the Pulmonary academic community for his work in bronchiectasis and non-tuberculous mycobacterial infections (NTM) and is co-Director of NYU Langone Medical Center's Bronchiectasis Program and co-directs its yearly Symposium on Bronchiectasis and NTM. The facts are what the facts are. I am just here to state them in a concise manner. You cannot clean a standard shower head.