For use between the bottom board and the brood chamber. Original design over 100 years old. NOTE: There is a top/bottom/front/back for this item. Shallow side UP, board toward front. Can be left on year round after installation.. Additional Details ------------------------------ Product description: For use between the bottom board and the brood chamber. Original design over 100 years old. Reduces swarming, increases egg laying in lower half of bottom brood chamber, decreases bearding. NOTE: There is a top/bottom/front/back for this item. Shallow side UP, board toward front. Can be left on year round after installation..