Can be used as teaching tools or research and decoration they are very beautiful. Glass , there are four lights, in of the lighting inputs of the lighting , from the three remaining lights, three basic colours and blue, respectively, are said three bases of the light. It's lightweight. And that is, three and blue lights, respectively the base light, of the remaining emitting , which is the light. It is of the most important accessories on the projector, the projector is capable of projecting color shadows on the screen, you which color of light is composed of three primary colors on the screen, an important color colors. Specification glass. Size: 20 mm x 20 mm x 2 mm. Package includes: 1 x glass