I really needed to organize and clean my electronics workbench. The boxes are long enough to hold breadboards with a little room to spare. The feet secure a top box to a bottom box to prevent them sliding off one another. Two of the smaller box (box3) can fit on the larger box (box2). Curious about box1? I'm learning Free Cad. We don't talk about box1. :P Both are 75mm high, and 200mm long. One is 150mm wide, the other 74mm wide. For 'Catagory', I know this is not a Character, but the system will not take the change I suggest.