Description This product is a double convex lens, made of high-grade glass, durable and practical. This convex lens has a diameter of 50mm and a focal length of 100mm, guaranteeing practicality through high performance. It's the perfect accessory for science experiments, suitable for science experiments and classroom presentations. Features - Material: Glass - Color: Transparent - Diameter: 5 cm / 1.97 inch - Focal Length: 10 cm / 3.94 inch - Double convex lens: The biconvex lens used to demonstrate optical principles and effects, the perfect accessory for scientific experiments. - Theoretical principle: Made according to the principle of refraction of light, it's thicker in the center and thinner at the edge. - Glass material: Made of polished glass with smooth edges, realistic surface, and clear vision, convenient to use. - Multiple occasions: Used for science experiments and classroom presentations, ideal for elementary, middle, and high school, and science museums and other occasions. - Science and education gift: This lenticular lens is a practical science and education gift for students and teachers who love physics and optics.Package list: 1 x Double Convex Lens