Queen excluders are used to do exactly what they are called - exclude the Queen. The excluders have a gap of exactly 4.1mm which allows the bess to pass from Brood chamber to the honey supers, while excluding the queen. This is to prevent the queen bee from laying eggs in the honey supers.
Our Queen excluders are made using slotted steel and have a wooden surround frame which ensures a tight fir to both super and brood chamber. Queen excluders must be removed in Autumn in preparation for overwinter.