This pine entrance reducer has two entrance sizes notched into it. You select the size you want by rotating it 90 degrees. The small notch is for winter, the large is for spring and fall. You can also use the small entrance to stop robbing, because it is easier for the guard bees to defend. For summer, you may not need it at all.
It is available in lengths for 8-Frame or 10-Frame hives. Can be used with Greenbeehives "IPK" screened bottom board, or standard pine bottom boards.