Use for Travel Trailers, Campers, Class A Moto Home, Fifth Wheel Trailers, Heavy Duty Trucks, Toy Hauler, etc,Suitable for the tightest distance of wheel down to 3.5" and extends to 12",Applying an opposing force to the two tires to prevents wheel shift,New electrophoretic technology is adopted in the production of the surface to prevent rust,Each box contain 2pcs Wheel Chock Scissor Stabilizers, 1 pc Crank Handle and 1 pc Socket Adapter