The double screened board makes combining hives or requeening easy and efficient.  To combine a weak hive or laying worker hive to a strong queen right colony, place the double screened board on top of the strong colony. Then place the moved colony on top of the double screened board.  Leave for 24 hours then remove the double screened board.  To requeen a colony in 2 boxes, remove the top box of bees and place the double screened colony over the bottom box.  Set the top box on the double screen board and open a back entrance.  The older foraging bees will return to the bottom box and the top box with younger house bees will be moore accepting of the new queen.