American Educational 5-Pack Unmounted Double Convex Lenses with Ground Edges -

American Educational 5-Pack Unmounted Double Convex Lenses with Ground Edges Brand: American Educational Five unmounted double convex lenses used to demonstrate optical principles in classroom and lab settings 75mm diameter double convex lens has a 17.5cm positive focal length Ground edges ease handling and ensure clear optics Plastic construction is safe and durable for all age groups Includes five 75mm diameter lenses