Commercial hives are exactly the same external dimensions as a National hive, but instead of having a rebate the hive is a simple cuboid.
Because of this the frames are larger and have shorter handles or lugs.
The brood box is picked up using small hand holds cut into the external wall of the hive.
Supers have this same feature, which can make them difficult to hold when full of honey.
Some beekeepers therefore use National supers on top of a Commercial brood box.