Calcium deficiency is a major dietary problem in captive reptiles. Exo Terra Calcium + D3 Powder Supplement contains high levels of phosphorous-free calcium as well as balanced amounts of vitamin D3 for optimal calcium absorption and to ensure long term health. Vitamin D3 aids in the proper absorption of calcium and is vital for captive reptiles not exposed to natural sunlight or ultraviolet lights. Contains the essential elements for proper metabolism: - Phosphorous free - Ultra fine powder - For reptiles