Based on the the principle that nurse bees deprived of a queen and brood will create queen cells to create new queens.
This box can be used in the first phase of the Dolittle method of raising queens.
Start by shaking about 5 pounds of nurse bees from frames with open brood, pollen and nectar frames. Grafted larvae added a few hours later.
Nurse bees will then start the cells which are transferred in 24 hours to a finishing colony and the nurse bees transferred back to their hive.
One well-stocked swarm box can start around 100 queen cells.
The use of the swarm box is described in Successful Queen Rearing by Marla Spivak and other queen rearing texts.