Our Ventilated Inner Cover allows you to move a colony without fear of suffocation. Screen or completely close the entrance and the bees will have over 1 1/2 square feet of ventilation space. It also provides better ventilation during the year reducing bees laying out. The inner cover frame is flat except for the 2 end pieces that are 3/8" higher. when the top is placed on the hive it rests on the end pieces leaving both sides open for air flow. Those of you, who like to experiment with ventilation, should give this one a try