Orion 7782 10.56-Inch ID Full Aperture Solar Filter A must-have for safe observation of the Sun through a 9.25" Schmidt-Cassegrain telescope without damaging your eyes Full-aperture 10.56" inside-diameter filter fits snugly over the front of your telescope to block 99.999% of incoming sunlight Glass elements are machine-polished and triple-coated with nickel-chromium stainless steel Each Orion telescope solar filter is mounted in a foam-lined aluminum cell featuring three equidistant securing thumbscrews, 4x 1/16" thick adhesive foam tabs, and 4x 1/8" thick adhesive foam tabs for customized friction fit to your telescope Note: All Orion solar filters are designed for use with an adequate friction fit attachment. Thumbscrews should ONLY be used to keep filter securely in place once a friction fit has been achieved