Galvanized steel plate with tan finish.
Diameter of the opening: 1.5"
Can be placed over the opening of a Bluebird nesting box or a Tree Swallow nesting box, so that squirrels and woodpeckers cannot enlarge the opening.
Dimensions of plate: 2'' x 2''.
Will work for :
Eastern and Western Bluebird
Will exclude :
Great Crested Flycatcher