The Cokin A164 polarizing filter eliminates glare / reflection e.g. from water, glass. It also increases the saturation of colors, it is very useful for increasing the intensity of the blue sky. On a sunny day - especially in the morning or evening - when the polarizing filter is used when the right angle between the shooting axis and the sun, the sky will be darkened intensely, and the clouds highlighted. This is one of the basic advantages of using polarizing filters and also the most commonly used. The intensity of the polarizing filter is adjusted by turning the ring in front of the filter and thus changing the polarization plane.