An inner cover allows moisture to escape and fresh air to be circulated throughout the hive when properly used with an outer cover. Our inner cover features a notched rim on one side for ventilation. During winter, turn the notch side of the inner cover down to provide an upper entrance and better ventilation. In the summer, turn the notch side up. Made of 1/4" smooth tempered Masonite, with a pine outer rim. Fully assembled