The Sigma 95mm Protective Filter is a clear, general-purpose protective filter designed to be left on the lens at all times. This filter helps to reduce dust, dirt, and moisture that could reach the front element of your lens and provides additional protection in case of drops or situations where scratches might occur.nnn- Provides no additional coloration or contrast, allowing you to pair this filter with othersnnn- The general protective filter reduces dust, dirt, moisture, and scratches that could reach the front element of the lens