Animal Essentials' Calcium Supplement is a natural calcified seaweed product harvested from the seabed off the south west coast of Iceland. Here amongst the cleanest and purest waters found any where in the world grows the small red seaweed Lithothamnium, which is composed of a wide variety of body essential nutrients, including calcium, magnesium, phosphorus, and potassium. With this product you can be sure your pet is getting enough calcium and essential minerals. Each batch is laboratory tested for purity! Animal Essentials Calcium is much easier for your companion to digest and fully utilize---meaning you can feed less and expect more!