In 2001, Dadant introduced their Brood Builder and I have heard glowing reports. B & B also introduced a product that I understand was used fairly extensively in Calif. I forget the name. 800-342-4811.
I have not tried either, as I always trap lots of pollen for my 100-hive operation.
Lloyd
Lloyd Spear, Owner of Ross Rounds, Inc.
Manufacturer of round comb honey equipment and Sundance pollen traps