It is the cage design that prevents Squirrels from being able to access this Essentials Squirrel Resistant Seed Feeder, in turn keeping the bird food safe and available for the birds that need it. 

There are two ring perches on the cage to make it easy for birds to feed on the food in the cage. 

This feeder is easy to fill with seed and to install on a bird feeding station or on a tree branch.