CALCIUM OYST W/D, TAB 500MG (60/BT 12BT/CS) Oyster Shell Calcium Tablets Plus Vitamin D Plus Vitamin D (200 IU). 500 mg Nutritional supplement. Compares to Os-Cal® 500+D Calcium Supplement with Vitamin D. Not Made with Natural Rubber Latex. Packaged: 60 Per Bottle, 12 Bottles Per Case Os-Cal is a registered trademark of GlaxoSmithKline.