The hardness of the peak of the eyebrow pencil core must meet the requirement of drawing a clear eyebrow line, but it cannot be so hard that it will scratch the user's eyes. The creation of product development personnel must consider that the product cannot be too soft, as this will dirty the area around the eyes; It cannot become hard when stored at low temperatures or left for a long time. The hardness or rigidity of the pen core is controlled by wax during the formation process, which can adjust the desired melting point when the product is completed.