Orion 07723 7.17-Inch ID Full Aperture Glass Telescope Solar Filter (Silver) A white light filter for safely observation of the Sun and sunspots through a telescope without damaging your eyes Optical glass filter fits snugly over your telescope's aperture to block 99.9 percent of incoming sunlight Filter inside diameter is 7.17 inch and it can fit telescopes up to 0.25 inch smaller - Fits Orion SkyQuest XT6, AstroView 6, SkyView Pro 6 and SkyView Pro 6LT reflector telescope optical tubes Each Orion telescope solar filter includes three equidistant thumbscrews, 4x 1/16 inch thick adhesive foam tabs, and 4x 1/8 inch 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