Designed to fit snugly over the aperture of your telescope, these optical glass filters block 99.999% of incoming sunlight, allowing you to safely observe sunspots and solar granulation in the Sun's photosphere. The Sun appears in a natural, whitish color. The glass elements are machine-polished and triple-coated with nickel-chromium stainless steel for a scratch-resistant surface. Each filter is mounted in an aluminum cell and supplied with foam tape liner to accommodate diameters up to 1/4" smaller than the nominal size.