Glass Solar Filter for Telescope, fits Orion ED 80/100, StarMax , Apex 102, AstroView 100, SkyView Pro 100 120mm\4.75" Glass Solar Filter for 101mm\4.00" Telescopes. This filter should fit the following telescope models: Orion ED 80/100, StarMax , Apex 102, AstroView 100, SkyView Pro 100 and instruments of similar outer diameter. Part #4750. Please read carefully: 120mm\4.75" is the diameter of the filter. The filter fits like a cap by friction. To be absolutely sure that the filter will fit, please measure the outer diameter of your instrument and make sure that it is not larger. Glass filters are the highest quality filtering material for observing and imaging sunspots and granulation, through telescopes and binoculars. The sun will appear in a natural orange color when viewed through your telescope using this filter. This is a high quality product of Thousand Oaks Optical, Arizona. A manufacturer of safe solar filters for over 30 years. Words of the producer: "The filters are made with high quality hand select glass coated with exclusive Solar II Plus coating. The most durable glass filter on the market. Guaranteed fifteen years." WARNING: ALWAYS MAKE SURE THE FILTER IS WELL ATTACHED TO THE TELESCOPE/BINOCULARS/CAMERA. IN CASE NECESSARY, USE STICKY TAPE TO SECURE IT. NEVER OBSERVE SUN WITHOUT A PROPERLY ATTACHED FILTER!