10-frame Metal Queen Excluder

This Metal Queen Excluder is a grid with slots that are large enough for a worker bee to get through but too small for a mated queen to pass through. The most common use is for it to be placed between the space where the queen lays eggs in the bottom couple of boxes and the boxes where extra honey is stored. Doing this helps keep the queen from laying eggs in boxes of honey that are to be harvested.
These excluders are made from metal which is more durable and easier to clean than plastic queen excluders. Bees treat both of them the same, so it is a beekeeper's choice.