This kit includes the phot rreg 37mm circular polarising filter the phot rreg 37mm uv filter the phot rreg 37mm adapter ring for gopro hd hero 3 3 and the phot rreg 4 slot filter pouch the phot rreg 37mm circular polarising filter helps to reduce reflections and glare by filtering out light that has become polarized due to reflection from a non metallic surface this results in a noticeable increase in the saturation of skies and foliage as well as clearer imagery when photogra