Our wheel tractor-scrapers have long been considered the basic method of moving volumes of material, and the Cat® 621 Wheel Tractor-Scraper is no exception. Known for its ability to be push-loaded and high travel speeds, it’s always an earthmover’s first tool of choice when working in challenging load areas. With an open bowl and a single engine, this machine is designed to handle a wide range of material types ranging from sand to ripped rock 609.6 mm (24 ") or less in size.