This Classic Series Slim Blue coat Filter from K&F Concept is a 72mm Bluecoat glass circular polarizing filter that helps reduce reflections and glare by filtering out light that has become polarized due to reflection from a nonmetallic surface. The light from the sun becomes partially polarized due to reflecting off electrons in air molecules, causing the light to scatter into what appears as haze. A polarizing filter arranges and filters directionally polarized light, allowing for the absorption of much of this light. This results in a noticeable reduction of glare and reflections from nonmetallic surfaces and an increase in the saturation of skies and foliage.

This filter is constructed from Japanese optical glass for clarity as well as color fidelity, and it features multicoating to prevent internal ghosting and reflections. It is made with an aluminum alloy filter ring that can be rotated to adjust the intensity of the polarization effect. The slim design reduces the potential for vignetting when used with wide-angle lenses.