Abstract: A system for measuring the height of a wind deflector mounted to the roof of a vehicle. A longitudinal base has a first end, an opposing second end, a generally planar top surface and a generally planar bottom surface. An adjustable stop is proximate the first end of the base and extends away from the bottom surface. A level indicator is affixed to the top surface of the base. An arm is spaced apart from the top surface of the base, and a displacement indicator is affixed to the arm. The displacement indicator displays information relating to the height of the wind deflector above the roof when the second end of the base contacts the wind deflector proximate the roof, the level indicator indicates that the base is on a level plane, and the displacement indicator is in contact with a top edge of the wind deflector.