This Vivitar Series 1 3-Piece Filter Set contains a variety of multi-coated glass filters that will optimize your photography experience, and protect your lenses from scratches and dust. The UV (ultraviolet) filter removes and absorbs UV rays, giving sharper contrast to your images, and minimizing the bluish cast often found in daylight conditions. The CPL (circular polarizer) filter is often used to increase the contrast and saturation in blue skies and white clouds, while not affecting the overall color balance of a shot. It is also useful for reducing reflections on glass surfaces and bodies of water. The ND (neutral density) filter reduces intensity of all wavelengths or colors of light equally, giving no changes in hue or color rendition. ND filters are particularly useful reducing depth of field in very bright light. ND8 allows 1/8 of available light into the lens (3 f-stops).