The B+W XS-Pro 67mm Clear Filter is for the sole purpose of protecting the lens of a camera. It is designed to produce no alterations in the characteristics of the actual photograph. Cameras can be very expensive pieces of equipment, even for the hobbyist, and dirty, scratched lenses can make them almost useless. Having a high-quality shield protects the lens and your investment in the camera.The XS-Pro is made in Germany. It is 67 millimeters in diameter and weighs 1 ounce. The rim is made of brass for strength. Brass is also less likely to jam when the accessory is being put on or removed. The rim is matte black in color to make it non-reflective. The glass in these transparent filters is made by Schott Glass, which is a company with a reputation for high quality. The color Schott uses for this product is Winter White.The XS-Pro is effective because of the coatings that are on the surfaces of the filters. B+W uses a multi-resistant coating (MRC) that protects against moisture, dirt, dust, and scratches. Applying multiple layers to a surface can introduce distortions as tiny imperfections in each layer add up to a cumulative effect. B+W uses an advanced process to avoid this possibility. The layers are applied in a vacuum. Gas ions are accelerated through the vacuum and pound against the surface, which compresses the layers of coating into a perfectly even sheet. The result is that the filters are harder than glass and repel water and dirt.One of the layers that are applied to the filter is an anti-reflecting layer that works across the full color spectrum. This is superior to filters that only have a single layer, as they are usually only effective for the yellow and yellow-green wavelengths. They can scatter the other colors of light and reduce the total contrast in the photograph. The MRC technology gives you broadband anti-reflection while improving overall light transmission. An uncoated lens will transmit about 92-percent of the light that hits it. With the MRC filter in place, about 98-percent of the light gets through.The last layer that is applied to the B+W XS-Pro is the nano layer. This takes the moisture-repelling properties of the filters one step further. It causes the water to form into almost fully circular beads, making it easy to absorb or brush off.The B+W XS-Pro MRC NANO has a 1x filter factor, which means it does not change the image. It is effective for both black-and-white and color photography. It helps prevent ghosting, internal flaring, and vignetting. Although the