From the Manufacturer:
Today, more and more people are beginning to understand the vital role natural ingredients play in the maintenance of proper joint function. Scientists everywhere are now recognizing the importance of chondroitin sulfate A and its numerous health benefits, especially with regard to joint function. Nature’s Plus addresses this need with Ultra Chondroitin 600, the highest potency, most concentrated chondroitin supplement ever developed. Ultra Chondroitin 600 is 100% chondroitin sulfate-A. Inferior forms of this nutrient such as chondroitin 6-sulfate and chondroitin-C are never used.