This item is an optical demonstrating model, which is a good tool for teaching. Made of acrylic material, it is clear and visual to see the . Suitable for better demonstrating the light convergence to students. The product is in a simple design, but it is very useful and practical. Features - Color: Transparent. - Material: Acrylic. - Size: About 5.80X3.00X0.90cm/2.28X1.18X0.35inch. - It is made of for durable and practical use. - Intuitive and specific, it is conducted to help students understand and learn. - Can be helpful for students to learn physics formula and the principle of light refraction. - Good for demonstrating optical principles and effects for students, learning about the properties of light. - Can be regarded as a great gift to children who are going to learn the principle of light convergence. Package list: 1 x cylindrical convex lens 1 x cylindrical concave lens 1 x semicircular lens 1 x equilateral triangle lens