I used to manufactures nana particulate colloidal silver 25 years ago and 30pmm using high voltage (it's the best way). I sold that business and always was a great fan at this amazing alternative to antiseptics that are harmful to animals and humans. I tried a couple of other manufacturer's products but I found this one to be among the most consistant for quality and speed of delivery when I need it quick and at a reasonable price. 25ppm is the best strength for the results I need and it works perfectly on my dogs eyes and ears. No more vet bills for crap antibiotics. I clean all wounds with colloidal silver and this one is the best out there for consistant quality and of laboratory standard. Thanks guys... I am hooked on your product and we love it.