Orion 07755 Deluxe Safety Film Solar Filter 4.57 Inch Inside Diameter (Silver) Explore the Sun safely through a telescope with this high-quality solar filter featuring Baader Astro Solar film in a sturdy aluminum cell Fits Orion Apex 102mm, ED80 refractor, Sky Scanner 100mm, and Star Seeker III 102mm telescopes Each filter is mounted in a foam-lined, clear-anodized aluminum cell featuring three equidistant securing thumbscrews for secure telescope attachment This filter has an inside diameter of 4.57 inch - it is designed to fit optical tubes with an outer diameter of 4.32 inch to 4.57 inch with included shim materials and securing thumbscrews 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