We've worked closely with queen breeders to develop our Langstroth Double Mating Nuc. Its larger size allows breeders to pre-grow frames which helps keep the bees from plugging out the frames. High-density construction provides optimal temperature stability Closeable entrance on each end 2 built-in feeders with queen excluders Holds 6 Langstroth mating frames (sold separately) Reinforced pry point doubles as a handle 2 removable bottom panels offer extra ventilation and easy clean out Stackable.