Ajax Scientific - LI142-0100 Polished Glass Double Lenses Spherical (Bi-Concave), 50mm Diameter, 100mm Focal Length
Ajax Scientific double Bi-concave lens. Made of polished glass with ground edges. Used for reducing the size of speading out light, with two inward curving symmetrical faces. 50-millimeters diameter. 100-millimeters focal length.