About Product:Product workmanship, writing smooth, safe and durable, no crack, no flow marks, no bubbles, fine and smooth, clear and clean after leaving, abrasion resistance, corrosion resistance, soft colors, fashionable and beautiful, visual effect is excellent, effective protection of the user's eye health. Inside and outside the box are using high strength industrial electrophoresis aluminum alloy, wear-resistant, tensile, non deformation, beautiful and durable, and maintain a smooth. For children learning exercises, essays business records, factory work shows a variety of occasions, such as the library