These swivel feed dispenser bowls are a reliable design that ensures your pets have easy and reliable access to clean feed. The back plate needs to be bolted in place over an appropriate sized hole in the mesh using the provided hardware. The door can then be opened and closed to enable the bowls to be swivelled out for changing of feed and water bowls. No need to enter the aviary, just swivel from the outside. Available in 3 sizes: 4 inch and 6 inch bowl diameters.