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: 200 mm focal length, Lens measures 2in diameter, 0.2 weight
Spectrum Tubes Deuterium, glass tubes approximately 10-1/4in (260mm) long, central capillary portion approximately 3-1/2in to 4in (90-100mm) long with electrodes sealed at both ends and connected to lead wires protected by metal caps.