This welding unit is based on the engine driven type, with the measurements based on the MIller Bobcat 250, at 40" long. The file printes two of them, and should be ordered in either the Frosted Ultra Detail or Extreme Detail. It has passed the software checks, so should print without issue. OF course, if there is a problem, contact me via the designer link, or diretly to Steve Nasburg at modelmechanic@gmail.com