Used to create ventilation in five frame Langstroth style NUC bee hives. Can also be used over a Miller Hive Top Feeder to feed without allowing bees to get inside from teh outside. There is a top and a bottom orientation to this unit. The flush side should be DOWN. Additional Details ------------------------------ Product description: Used to create ventilation in five frame Langstroth style NUC bee hives. Can also be used over a Miller Hive Top Feeder to feed without allowing bees to get inside from teh outside. There is a top and a bottom orientation to this unit. The flush side should be DOWN. Style: Vintage