The Tiffen 4.5" UV 17 filter is a general-purpose clear filter that helps to absorb ultraviolet light and reduce the bluish tint of daylight. This filter is particularly useful for photographing at high altitude or near bodies of water. It adds no additional colouration or contrast, allowing you to pair it with other filters. This filter attenuates approximately 97% of UV rays, slightly less than a UV 2A filter.nnThe UV filter is also useful as a general protective filter to leave permanently on lenses. Filters help to reduce dust and moisture that could reach your lens element and provide additional protection in the event of drops or situations where scratches could occur.nnTiffen filters are manufactured using ColorCore technology; a process that involves laminating the filter substrate between 2 pieces of optical glass, polishing it flat to a tolerance of 1/10,000th of an inch, and then mounting it on precision metal rings.nnnFeatures:nn- Absorbs 97% of UV light and reduces the bluish tint of daylight.n- The clear filter adds no additional colouration or contrast, allowing you to pair it with other filters.n- The general protective filter reduces dust, moisture and scratches that could reach lens elements.nnnSpecifications:nn- Type: UVn- Size: 4.5" / 114.3 mm (diameter)n- Grade: UV 17n- Filter Factor: 0n- Effect: Absorbs UV rays and reduces the bluish tint of daylightn- Construction: ColorCore Technologyn- Front Filter Thread Size: 4.5" / 114.3 mm (diameter)n- Front Lens Cap Size: 4.5" / 114.3 mm (diameter)