Versele Laga Prestige Grit with Coral is a tried tested mixture of oyster shells, grinding stones, seashells, redstone charcoal. All of which are an essential food supplement for caged birds as it provides minerals trace elements as well as acting as the teeth of a bird in their crop. Analytical constituents Crude ash 98.5%, Calcium 23%, Phosphorus 0.02% Sodium 0.15%