1、Solar Film Substance: It is actually a solar filter, but different from a solar filter. Astronomical telescopes must add a filter to observe the sun. Otherwise, it will damage the eyes and instruments. The sun is so bright that it is easy to find the sun in a telescope, even with the addition of a solar film. 2、Advantages of Solar Film: The advantage is that the solar film is not easy to break, suitable for natural environment for a long time, especially in photography, do not have to be afraid of the wind and rain. When the film is dirty, it can also be cleaned casually with clean rags and paper towels, and even water washing is not a problem. 3、PET Coated Aluminum Foil Film: This solar observation film is called solar film in the industry. Reddish yellow sun is seen through the film solar filter. Can be used to do naked eye observation for visual use, also used for astronomical photography. 4、Conforms to ISO Standards: The second generation solar film is a bright silver colored film material on both sides. Thickened design, safe and solid observation experience. The product meets the ISO standard solar filter film can protect your eyes when observing the sun, if you encounter the sun film appears to leak light before use please stop using it immediately. 5、Light and Radiation Reduction: Sun films reduce light and radiation without reducing the contrast of the subject, which means that using a sun film as a solar filter can result in a better image quality, and can even easily record the sun's surface spacer activity. 1 x Film Solar Filter  Item Type: Film Solar Filter Weight: 270g / 9.52oz Material: Aluminum Alloy, PET, Aluminum FoilBezel Outer Diameter: Approx. 19.4cm / 4.57inSupport Objective Lens Diameter Range: Approx. 16.4-19cm / 6.46- 7.48inThrough Light Caliber: Approx. 17.2cm / 6.77inScrew: M5 16mm