The Cokin 58mm PURE Harmonie Circular Polarizer Filter helps to reduce reflections and glare by filtering out light that has become polarized due to reflection from a non-metallic surface. A polarizer is able to absorb much of this polarized light and, in turn, increase the saturation of skies and foliage, cut through distant haze, and minimize reflections in glass and on water. A circular polarizer differs from a linear polarizer in that it integrates a quarter wave plane within a linear polarizing filter. The addition of this helps to circularly polarize reflected light, which enables your camera's autofocus and auto-exposure mechanisms to function properly. The EVERCLEAR 5 Coating Technology is a multi-layered coating applied to the filter substrate in order to provide protection against five distinct elements: water, oil, dust, soil, and scratches. In addition to the multi-layer coating, this filter also features an incredibly thin design, measuring just 4.5mm thick. This slender profile is ideally suited for use with wide angle lenses in order to prevent vignetting. It does not have front threads for stacking additional filters, but will accept standard lens caps.