Description This item is optical demonstrating concave lens model set, which is good tool for teaching. Made of premium material, it is clear and excellent to use. Suitable for better demonstrating the optical knowledge to students. The product is in simple design, but it is very useful and practical. Features - Color: Mainly black. - Material: Plastic. - Size: 14.00X7.50X7.50 cm/5.50X2.95X2.95 inch. - It is made of premium material for durable and practical use, excellent and safe, for long time use. - Intuitive and specific, it is conducted to help students understand and learn physical optics. - Can be helpful for students to learn physics formula and the principle of light refraction, can do optical experiment. - Good for demonstrating optical principles and effects for students, learning about the properties of light. - Can be regarded as great gift to children who are going to learn the principle of optics. It is made of premium material for durable and practical use, excellent and safe, for long time use. Intuitive and specific, it is conducted to help students understand and learn physical optics. Can be helpful for students to learn physics formula and the principle of light refraction, can do optical experiment. Good for demonstrating optical principles and effects for students, learning about the properties of light. Can be regarded as great gift to children who are going to learn the principle of optics.