Natural light from the sun and sky has a balanced spectrum, rendering colors perfectly. However, most artificial bulbs emit light in only a narrow scope of the visual spectrum. Aero-Tech's FULL element (neodymium oxide) mixed directly into the glass which has a natural filter to diffuse the dull yellow/green portions of the spectrum. This produces truer more natural colors and has been found to have a positive effect on how people perceive their surroundings. Great for pets and plants, too! Made in the USA with glass from Europe where most of the world's neodymium supply is found. However, the CFL bulbs are Not Made in the USA.