This kit consists of a Circular Polarizer, MC Protector filter and case. Circular Polarizers Light rays which are reflected become polarized. Polarizing filters are used to select which light rays enter your camera lens. They can remove unwanted reflections from non-metallic surfaces such as water or glass and also saturate colors providing better contrast. The effect can be seen through the viewfinder and changed by rotating the filter. The filter factor varies according to how the filter is rotated and its orientation to the sun. Filter factor is between 2.3 and 2.8 (approx. +1.3 stops). Circular polarizers are specifically designed for use with auto-focus SLR cameras (They will also work on manual systems and video cameras without problems). MC Protector Filter MC (multicoated) Protectors are wise initial investments. They help protect your valuable investment from dust, moisture and scratches, which can lead to costly repairs. They can be left on at all times.