Opteka 27mm High Definition II Multi-Coated Circular Polarizing Glass Filter For shooting in bright sun, at beaches, snow, etc. Controls bright light entering lenses for a better balanced color image. Darkens blue skies and reduces reflections from non-metallic surfaces Increases saturation in the blue range of the spectrum, i.e. skies, water Mount rotates to control amount of effect Multi-Coated and heat treated glass to eliminate distortion and minimize light reflections Brand New, Lifetime Warranty