This is a simple guard that reduces the entrance size of any conventional hive. It can help protect from mice or inter-hive competitors, etc.
I have a smaller Printrbot Simple Metal, so the full length (15.25") wouldn't fit on the board so I divided it up into 3 sub-6" pieces that can be easily and seamlessly be connected.
The guard can also be rotated so that nothing can enter or exit (when you need to move a hive/work on or around it). This is facilitated by the separate connector plates (x2) that you can screw into the hive. The guard then just slides in.
So far it has worked very well on the hive. Honey bees are able to pass easily in and out of the hive.
Feel free to let me know if you have issues or questions!