Zomei 72mm CPL Filter CIR-PL Circular Polarizing Filter for Canon Nikon Sony Olympus Pentax Camera Lens 72mm Description: A polarizer is an optical filter that passes light of a specific polarization and blocks waves of other polarizations. It can convert a beam of light of undefined or mixed polarization into a beam with well-defined polarization. The common types of polarizers are linear polarizers and circular polarizers. Polarizers are used in many optical techniques and instruments, and polarizing filters find applications in photography and liquid crystal display technology. Polarizers can also be made for other types of electromagnetic waves besides light, such as radio waves, microwaves, and X-rays. Feature: Circular Polarizer filters are used to reduce reflections from non-metallic surfaces (windows, water and so on) and increase density within the sky and/or foliage by absorbing reflected light. They also allow to emphasize details such as clouds and makes pictures crisper, with deeper color tones. Their effect cannot be achieved with a computer software. Package: 1 x 72mm CPL filter As our filter just different in size ,so here we just use one size show our products and package