Scrubbers are large vertical cylinders with hundreds of small cloth strips attached to them. The scrubbers rotate rapidly, anywhere from 100 to 500 rpm, spinning the cloth strips until they are perpendicular to the cylinder. Although the cloth strips are quite soft, it would feel like a whip if you got hit by them. Scrubbers normally have hydraulic motors that spin them. There is at least one scrubber on each side, and there may be two or more. As the car moves past the scrubbers, the cloth strips brush along the vertical surfaces of the car.
Some car washes also have wrap-around washers. These are scrubbers on short booms that can move around to the front and rear of the vehicle, scrubbing those vertical surfaces as well. Like most of the mechanical equipment in the car wash, the washers are run by a combination of electric motors and hydraulics. Normally, a single, large hydraulic power unit is connected to all of the various hydraulic pumps throughout the car wash.
The cloth used in the scrubbers is very soft and regularly cleaned to ensure that there is nothing caught up in them that could scratch the cars. They are replaced once they become worn or too soiled to clean effectively.
In addition to the mitter curtain and scrubbers, a lot of car washes have a high-pressure washer.