This set of tool boxes is the type that mounts to the frame of a semi either under the cab doors, or occasionally behind the cab on the frame. This is a set of 12, that are 24 scale inches wide, and have passed the software checks. If there's a problem, contact me via the designer link or via email to modelmechanic@gmail.com Be sure and 'follow' me as a designer to have the easiest access to my store and new releases.