A beam splitter is a high-precision tool used in experimental laboratories. It is a glass cube made of several lab-grade glass prisms with special optical filtering coatings. This type is also called an x-cube. A beam splitter’s purpose is to literally split a single beam of light into multiple beams. This may sound simple, but it requires fantastic precision. They are typically used to separate a single laser beam into multiple beams, but this dichroic version can split a beam of white light into different regions of its spectra.
Try shining a light, such as a cell phone flash light, through one of the faces and see the different colors that make up the white light spill out the other sides.
Each comes in a foam-padded acrylic box.