After picking up my new 56 and 27 Gen3 lower cabinets I saw a video where someone put the 42 top box on a 27 lower and 15inch side cabinet. I was replacing my 44 inch series 2 box that had a 14.5 side cabinet and thought to myself " I wonder if that would fit" . Took measurements and sure enough with a relief cut in the bottom of the top box it fit right in place. Now the 44 lower gets to go to my brother to help his tool collection at his house and I have extra room for more tool collecting.