Double screen board. Used for dividing hives on the same bottom board, swarm control or as a vented top when moving hives.. Entrance on top and bottom sides are on opposite ends. #8 hardware cloth. Simple design has no moving parts to get propolized and can easily be closed with wooden plugs or duct tape when necessary.
Note that picture is of the 10 frame version. 8 Frame version is similar but 13-3/4" wide instead of 16-1/4" wide