Supa Cage and Aviary Bird Grit, 3 Litre Bucket, Combination Of Soluble & Insoluble Grits and Charcoal Which Aids Good Health, Aids Digestions And Increase VitalitySupa Cage & Aviary Bird Grit 3 Litre (Pack of 1) contains a mixture of graded soluble and insoluble grits with added charcoal which aids good health, aids digestions and increase vitality. The soluble grit is Limestone Grit & Crushed Sea Shells which provides a source of Calcium that is essential in a birds diet. The insoluble grit is Flint Grit which the birds store in the crop gizzard where it acts as a grinding agent to assist digestion of seed &