The Sigma 105mm WR (Water Repellent) Protector Filter is a simple, clear filter with a 1x filter factor and is designed to provide general protection for your lens. This optically clear filter does not affect overall image quality while helping to prevent dust, scratches, moisture, and other elements from reaching or damaging your lens. This filter is multi-coated to eliminate internal ghosting and reflections. An anti-static coating serves to limit the accumulation of static electricity, making dust particles easier to remove or preventing them from adhering to the filter. Additionally, a water-repellent coating results in an improved beading effect when in contact with water, as well as oil, for greater cleaning efficiency while enhancing scratch resistance.Sigma WR Protector filters are constructed from optical glass with a black rim. Set within an aluminum-alloy filter ring that is durable while remaining lightweight, the glass provides increased clarity as well as color fidelity while the black rim further ensures that reflections do not occur along the filter's edge