Reptile One calcium + D3 powder is specially formulated for use in supplementing your amphibian & reptiles diet to assist with calcium absorption. Vitamin D is essential for captive amphibian or reptiles that may not be receiving sufficient natural sunlight or UVB. Sufficient calcium + D3 in your animal will promote healthy bone growth, nerve functions and hormone synthesis. The Lack sufficient D3 in your amphibian or reptile may lead to insufficient absorption off calcium. Reptile One's Calcium + D 3 formula is low in phosphorous and has been manufactured to an ultra fine grade for easier absorption through the animal cell membranes. Suitable for regular use in dusting insects or vegetables which are then fed to your animals.