We have used these insulated hive tops on our hives for the last several years with good results. The M-V insulated hive top takes the place of your inner cover for the winter. The cover’s design allows the moist air emitted from the respiration of the wintering bees to enter and be wicked into in the cellulose insulation thereby preventing it from condensing and dripping back down on the winter cluster (which is what frequently happens when a normal inner cover is used on a hive as the inner cover is often the first cold horizontal surface in the hive). The M-V insulated cover consists of 3 ½” deep rim with screened ventilation holes around the perimeter which allow water to wick away out of the insulation. The holes are inclined upward to prevent rain and snow intrusion. The top and bottom of the rim are covered with 1/8” hardware cloth (with 3/4″ of space at the bottom to accomodate emergency feed or winter patties). The lower rim is notched to provide an upper winter entrance/exit for the bees. Sandwiched between the top and bottom layers of hardware cloth is a layer of 1/2″ filter fabric material followed by approximately 2 inches of cellulose insulation and another layer of 1/2″ filter fabric.