Here is a link. After you open it, click the "Download PDF" on the right to make it user friendly to review. Shower Clear is the only Shower Head of over 650 Tested mentioned in the Study. See Storage Study.. file:///C:/Users/Owner/Desktop/Ecological%20Analyses%20of%20Mycobacteria%20in%20Showerhead%20Biofilms%20and%20Their%20Relevance%20to%20Human%20Health%20_%20mBio.html