The entrance to the hive which is created when placing the deep super on the bottom board enables the placement of an entrance reducer and limits bee access to the hive, as well as controls ventilation and temperature during cooler months. The entrance reducer is placed loosely at the hive's entrance...the two notches reduce the entrance of the hive: the small notch leaves an opening about the width of a finger while the large notch is about four finger widths. The entrance reducer can be removed altogether so as to completely open the entrance. The entrance reducer is primarily used for newly established hives or during cold weather; it isn't necessary in warm weather, except maybe when you're dealing with a robbing situation. In the absence of an pre-cut entrance reducer, grass or sticks may be bundled and placed into the opening to limit access.