Since 1994, Npsw Has Provided Health Food Stores, Practitioners And Loyal Customers The Highest Quality Colloidal Silver On The Market. | Natural Path / Silver Wings 250 Ppm And 500 Ppm Colloidal Silver Can Be Diluted To 10 Ppm, Thus Making It Colorless. | Many Of Our Customers Prefer To Take A Full Strength Dose As Needed. Our Colloidal Silver Is Guaranteed To Be A Pharmaceutical Grade. Highest Quality !!