Rivers of Health has been producing High Stability Colloidal Silver for many years. They use the latest electro-current controlled technology and a 9 stage water purification process. The very small particle size means that it can be more effective than some other products with a higher silver content. The small particle size also improves the stability of the product as there is less of a tendency for the silver particles to agglomerate or settle out, and hence this product has a shelf life of at least 12 months.