Orion 7790 12.13-Inch ID Full Aperture Solar Filter A must-have, white light filter for safely observing the sun and sunspots without damaging your eyes Optical glass filter fits snugly over your telescope's aperture to block 99.999% of incoming sunlight Glass elements are machine-polished and triple-coated with nickel-chromium stainless steel Filter is mounted in an aluminum cell and supplied with foam tape liner - fits Orion SkyQuest XT10, XT10i IntelliScope, XT10g GoTo Dobsonians and Atlas 10 reflector telescopes 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