Such ruler is made aluminum alloy of materials in which makes itself getting great popularity. There are 2 different types, blue & black ,purple & black, colorful apperance. Cute foldable ruler with locking button, it's lovely, and easy to carry. Great for children, student to use at home school, and office staff. Draw many patterns of square, star, for triangle, round, for heart-shaped, building up an interesting painting, improving children's imagination., Manufacturer: Pnuokn