Review on 🌈 Enhance Visual Experiences with Rainbow Symphony Diffraction Grating Glasses by Robert Dabney

I am using them to demonstrate spectroscopy. Glasses with a diffraction grating separate the wavelengths of light into their component parts, making it easy to determine what "colors" the light source is emitting. It's "linear" which means you get an axis. There are versions of this that create multiple axes (which looks really cool but isn't that useful for teaching purposes). I buy them in bulk from time to time as they are mostly given away for free. It's too expensive to buy in small batches when you give one to each audience.