These glasses produce "psychedelic" rainbow color effects. With these glasses bright objects give a colorful halo like effect that changes as you view the object from different distances and angles. The effects vary depending on the lighting situation, your point of view, tilt of your head, etc. The effect can be quite amazing and often very beautiful. Objects such as chandeliers and candles are simply beautiful to view with these glasses. Different types of light sources produce different types of rainbow like effects. These are great for viewing fireworks, laser light shows, Christmas lights, and make great party gifts. These specially treated holographic diffraction grating lenses separate beams of light into a color spectrum producing a beautiful rainbow-like effect. The type of light, color of light, angle, and intensity, all effect how the light is broken up. These are great tools for studying light. These glasses are known by many different names: "3D fireworks" glasses, "psychedelic" glasses, "prism" glasses, "magic mushroom" glasses, "Rainbow" glasses, "acid" glasses, "rave" glasses, "diffraction" glasses, "Disco" glasses, "LSD" glasses, "Christmas Tree" glasses, etc. These particular glasses are high quality. The lenses for each eye are perfectly matched up so that both eyes see the same visual effects in 3D. With some of the cheaper glasses, both eyes do not see the same visual effects (this can cause headaches for some people). Glasses are constructed of very rigid paperboard. These Glasses are designed to fit both large and small head sizes (with two separate bend points for each ear piece). However, they do not fit very small children.