led substrate lens. led substrate lens . Crystal materials: 99,996% of Al2O3, High Purity, Monocrystalline; Crystal quality: Block marks, twins, Color, micro-bubbles and dispersal centers are non-existent; Diameter: 2inch-6inch Note: The LED substrate can be provided according to your specific requirements; If there is anything we can do for you, please dont hesitate to contact us.