Thin Pockets® are more flexible and easier for your bird or other animal to manipulate the holes to acquire their individual pellets. They are made of 3-4 oz leather . Fill Parrot Pockets® with your birds dry pelleted diet or any other dry good idea for longer occupational time while you work! The diameter of the holes are made for diets like Harrisons Bird Food or ZuPreem african grey sized pellets. This Pocket size is intended for medium parrot species such as large macaws or cockatoos at 5" wide by 8" tall.