The Sigma 105mm WR UV Filter is a general use, clear filter that helps to absorb ultraviolet light and reduce the bluish cast of daylight. This filter is especially useful when photographing at high altitudes or around bodies of water. No additional coloration or contrast is provided, allowing you to pair this filter with others.A UV filter is also useful as a general protective filter to leave on a lens at all times. This filter helps to reduce dust and moisture from reaching your front lens element and provides additional protection in case of drops or situations where scratching could occur.This Sigma WR UV Filter is coated to repel water drops and resist smudging from fingerprints. It is also treated to exhibit antistatic properties to prevent microscopic dust from clinging to the front surface. This helps to ensure sharp images