Double Convex 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, for educational uses, Size: 200mm focal length, 2in diameter and 5.5mm thick
Diffraction Grating Glasses, 500lines/mm, Highly efficient, Single axis holographic diffraction grating lenses separate light from any source into its spectral components for study/analysis, Used with Power Supply/ Spectrum Gas Tubes, Make study of light easy