This 6-piece acrylic lens set includes one each of: double convex (20cm focal length), double concave (20cm focal length), plano convex (25cm focal length), converging concave-convex (25cm focal length), diverging concave-convex (25cm focal length), and plano-concave (25cm focal length). Each lens measures 1.5 inches (50mm) in diameter with brushed edges and polished faces. The lenses are stored in a hinged wooden box with foam inserts measuring 4.5 x 3.5 x 2.5 inches. Educational grade optics suitable for basic optics study in physics classrooms.