Calcium Supplement. 2 In 1 Dual Action. Bone Strength & Flexibility. Includes Magnesium & Zinc. Includes key essential minerals like magnesium to help support collagen production for stronger, more resilient bones. Caltrate 600+D3 Plus Minerals has calcium plus collagen-supporting minerals to help your bones stay strong and flexible. Additionally, Caltrate Plus Minerals has the most vitamin D3 to help maximize calcium absorption to support stronger, healthier bones.