Double Concave Optical round Lens, Material: Glass, designed for physics and educational uses, Because of their educational use design, there may be minor imperfections that do not affect physical function, Size: 250mm focal length, 50mm diameter and 3mm thick
Double Convex Lens, Highly polished, optically true lens is excellent for physics classroom demonstrations in optics and light refraction, with ground edges, great for physics classrooms, with highest grade, Size: 300 mm focal length, Lens measures 3in diameter, 0.1 weight