It is a specialized type of trim used to finish the edge of a staircase. It is designed to provide a smooth transition between the flooring material on the stairs and the adjoining floor at the top or bottom of the staircase. The curved profile allows for a seamless transition from the horizontal floor surface to the vertical stair riser. The other side of the molding is designed to be flush with the top surface of the flooring material, ensuring a smooth and even transition.