Circular Polarizer CPL Filter - A circular polarizing filter is used to darken skies, manage reflections, or suppress glare from the surface of lakes or the sea. A linear polarizer can be used to change the balance of the light in the photograph, providing a bluer sky and clearer water. | Magnetic Design - SmallRig CPL filter kit 4727 can be installed and removed the filter via magnetic attraction. Enhanced magnetic attraction is safe and reliable, and photographers can quickly and efficiently switch filters according to different needs for light. | Phone Cage Compatibility - It comes with a m-mount filter adapter and can be compatible with SmallRig mobile phone cages 4407 / 4473/ 4391 / 4392 / 4393 / 4396/ 4397 / 4398 for iPhone 15 series. Please note that it does not fit the M-mount phone cage in other brands. | Camera Lens Compatibility - This circular polarizing filter comes with a 67mm threaded filter ring, which can install the magnetic filter on a 67mm camera lens, providing a convenient magnetic filter installation experience for camera lenses. | Multi-Coating AGC HD Glass - This CPL filter is made of premium AGC optical glass and true color film, which improves the light transmittance while ensuring the image quality without color cast. The 28-layer nano coating on both sides protects the filter against water, dirt, oil, and scratches. And the filter frame is made of CNC-processed aluminum alloy to avoid vignetting and dark corners under the ultra-wide angle lens.