Why Calcium 1200 MG Sustained Release with Vitamin D3 1000 IU? Bronson Calcium Sustained Release provides 1200 MG of Calcium per serving plus Vitamin D3 and Magnesium. Our Sustained Release formula slowly releases over time to provide a steady balance of Calcium throughout the day.* Laboratory tested GMO-Free, Gluten-Free and Soy-Free, Bronson Calcium Sustained Release is in-house tested and carefully manufactured by trained professionals in our state-of-the-art facility that is located in Hauppauge, New York.   About Bronson Since 1960, Bronson has been providing families with the highest quality products and finest customer service available. This 60-year heritage speaks for itself. But with so many online vitamin stores, why should you purchase supplements from Bronson? In short, our company is time proven, offering the purest, high quality vitamins backed by science. Trust Bronson to provide the very best natural health products for you and your family.