An entrance reducer is a thin strip installed in the entrance of a bee hive. It is typically made of wood, but it can also be made of metal or plastic, with a notch, or sometimes two. The main purpose of a reducer is to restrict or reduce the size of the entrance to a size that is easier for the bees to defend against raiding bees, pests and rodents. In the winter months it aids the bees in temperature regulation of the hive.