BONEFIDE II AT Tablet contains Algae Calcium (Aquamin), most bioavailable calcium source, and 100% RDA of vitamin D3 which together may improve bone density and strength. Vitamin K2-MK7 in BONEFIDE II AT is essential for the absorption of calcium ensuring that calcium reaches the bone and not arteries. Multi-source calcium tablet formula with stabilized Vitamin K27 (MK-7). Vitamin K27 (MK-7) helps in strengthening of bones health and increasing bone density. Contains Vitamin D3 which improves the absorption of calcium