This round CPL filter is made of high quality optical glass. Great clarity. No loss of sharpness or color drift. Both sides of the filter glass are polished to balance the light penetration path and ensure image quality. Polarizing filters are treated with 24 layers of surface coating to protect the lens from water, scratches and oil. The filter coating also helps minimize reflections. Tip: The reflective surface should form an angle of 45 to the line of sight for best reduction of reflections through the filter. The grip of the frame is very good. It is easy to put on and take off. The aeronautical aluminum mount is very thin (thickness: 5.3 mm) to avoid dark corners when using wide angles. This lens filter is compatible with all lenses of 'a diameter of 62 mm (a "" symbol appears on the lens to indicate the diameter). It allows the lens cap and lens hood to be mounted directly on the filter. Note: If the CPL filter is very tight and stuck to the lens, this may be due to incorrect mounting and can be removed by increasing friction using a cloth or rubber band.