Self-Propelled is a term that is typically applied to farm machines with integral power units that are capable of moving about as Well as performing some other simultaneous operation such as harvesting or spraying a crop.

-See also:
"Self-Propelled" is in the HS Code "8429"
Self-Propelled Bulldozers, Angledozers, Graders, Levellers, Scrapers, Mechanical Shovels, Excavators