Warner Marine Research Concentrated Strontium Supplement is the premier Strontium product available today. It is produced entirely from Analytical Reagent Grade (A.C.S.) Strontium Chloride Hexahydrate, the highest quality raw material in the hobby. Warner Marine Research is the only manufacturer to use these fine quality raw materials. Most importantly Warner Marine Research Concentrated Strontium is highly effective at adding high quality bio-available Strontium without the unneccesary impurities found in the competitors products.