B00DJM4PXY Sigma 50-500mm f/4.5-6.3 APO DG OS HSM High Grade Multi-Coated, Multi-Threaded, 2 Piece Lens Filter Kit (95mm) Made by Optics + Nwv Direct Microfiber Cleaning Cloth.

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UV Filter (ultraviolet) Haze (1A) for protection against dust, dirt, scratches, fingerprints and the sun’s ultraviolet rays.
Circular Polarizing Filter. Used to increase color saturation, like darkening blue skies so that white clouds stand out.
10 year warranty