The Dolly Master is an air-operated, truck-mounted steel frame assembly that includes a vertical slide with guide ramps to which a 1.75 inch (4.45 cm) diameter coupling pin is attached. A double-acting air cylinder, which uses the truck's air supply, raises and lowers the slide. A cab control valve is operated from within the cab.
The Dolly Master can be bolted or welded to the tow vehicle. It has few moving parts so it is easy to maintain.
The Dolly Master is NOT intended for use in trailer spotting or coupling.