Links LIQUID CALCIUM K2 WITH VITAMIN D3 is a clinically formulated bone health supplement that comes in a smooth, great tasting liquid. It contains calcium to help maintain healthy bones in adults. Links Liquid Calcium K2 with Vitamin D3 features vitamin K2 as menaquinone-7 (MK-7), a clinically tested highly absorbable form of vitamin K. Exciting research shows that vitamin K2 directs calcium out of the arteries and into the bones. Vitamin K2 also protects the heart. Vitamin D3, also known as cholecalciferol, is the preferred form of vitamin D because it is the same specific form of vitamin D that is produced by the skin upon exposure to sunlight and hence more effective than other forms of vitamin D.