Designed to adjust the size of the tap holes in the hive and prevent the hive from mouse attacks in autumn and winter. The mouse hive attacks in autumn and winter. The entrance disc of the beehive box is used on a box where there is a round entrance hole A rotating disc used to control access to the entrance of the hives. Beehive nest door vents have four access options: fully open, queen exclusion, closed with ventilation, and fully closed. Install it on the hive to allow bees to enter and exit easily. Curtain Track Rollers-100pcs Inner Rail Curtain Hook Rail Slider,Plastic Curtain Pulley(White)