This Inner Cover is about 3 inches thick it also has a whole in the center. It also has a notch in the lip to give your hive an upper entrance and help with ventilation. The extra deep thickness allows you to add insulation for the winter. Adding Insulation for the winter will help reduce condensation and moisture in your hive.
The hole allows the inner cover to work with both the Hive Top Feeder or the Plastic Feeder Pail