These Pockets are for tough beaks that are advanced foragers. They are made of 8-9 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 leather on this Pocket series is far harder to open the holes for our foraging friends. The diameter of the holes are made for diets like Harrisons Bird Food or ZuPreem conure sized pellets. This pocket size is intended for larger parrot species such as conures, pionus or caiques at 4" wide by 6" tall.