This is learning handheld concave lens tool used to understand the physical optics experiment more intuitively. It can stimulate students' cognitive ability in physics and is good partner in school teaching. Use the school for teaching, etc. material that can ensure its durability and practicability. Features - ColorSilver - Material: Plastic, metal. - Size: 14.50X3.50X1.50 cm/ 5.70X1.38X0.59 inch. - Made of premium quality material, professional and durable, excellent and easy to clean. - The product can effectively explain the knowledge of physical optics with experiments. - Used in scientific experiments and classroom demonstrations. Perfect and wonderful for labs use. - The handheld concave lens are useful teaching instrument for children learning optical knowledge. - You can experiments and demonstrate optical principles and effects for kids. Package list: 2 x handheld concave lens