Gain the assurance you need to be Ready for the Road Ahead , with the Holland Fifth Wheel Dolly Master Low Lift. With a sturdy steel frame and vertical slide with built-in guide ramps, this replacement kit is able t to move the slide assembly up and down as needed with the help of an air supply. To ensure convenient control of the Dolly Master, a control valve is inserted inside the vehicle cab. FleetPride is your First Click in Heavy Duty .