A floor scrubber is a machine that uses brushes or pads to scrub floors and remove dirt and grime. It typically operates by releasing cleaning solution from its built in water tank onto the floor and then using its scrubbing tool to agitate the dirt and debris.

An auto scrubber is a type of floor scrubber that is self-propelled and can operate without operator assistance. It typically has larger tanks for both cleaning solution and recovery. Unlike the floor scrubber, the auto scrubber has a built in vacuum motor that collects the dirty water into its recovery tank, leaving the floor clean and dry. Auto scrubbers are often used in large facilities such as hospitals, schools, and warehouses where cleaning a large area quickly is necessary.

In summary, while both floor scrubbers and auto scrubbers are used for scrubbing floors, auto scrubbers are self-propelled and generally have larger tanks and more advanced features than regular floor scrubbers.