General description A tough squirrel-proof dome designed to protect bird feeders and feeding stations from squirrels and other climbing food stealers. If squirrels or rats are attacking your bird feeders, this could be the solution. Technical specifications Diameter: approximately 15" (38 cm) Hole size: approximately 3 cm Compatibility and accessories Designed for use on feeding poles with adapters for 12 mm, 22 mm, and 25.5 mm poles Compatible with feeder poles, shepherd's hooks, and pole feeding stations