Hit a triple play with our high-quality Calcium, Magnesium and Vitamin D! Each of these nutrients plays an essential role in maintaining bone health. Calcium and Magnesium are also important for muscle contractions, and Vitamin D contributes to immune system health. Coated tablets deliver 400 I.U. Vitamin D, 1,000 mg of Calcium (as Oyster Shell), and 500 mg Magnesium per serving.