Features 1、Related Parameters: Outer diameter of the frame 176mm, support objective size range 144‑170mm, light aperture 152mm, screw M5 16mm. 2、Solar Film Essence: In fact, it is a solar filter, but it is different from a solar filter. Telescopes must be fitted with filters to observe the sun. Otherwise, eyes and instruments will be damaged. The sun is so bright that it is easy to find the sun in a mirror, even with a solar film. 3、PET Coated Aluminum Foil Film: Defined as a solar film, this solar observation film is called 'solar film' by astronomers, and it is called solar film in the industry. Solar film as a new product, the name only represents such a product, it can be used for visual observation of the naked eye, but also for astrophotography. 4、Solar Film Advantages: The solar film looks at the red and yellow sun, while the traditional film looks at the grey sun. The advantage is that the solar film is not easy to damage, suitable for long term use in the natural environment, especially in photography, do not be afraid of wind and rain. When the film is dirty, you can also clean it with a clean rag and paper towel, or even wash it with water. 5、Reduce Light and Radiation: Solar film in the reduction of light and harmful radiation at the same time, will not reduce the contrast of the subject, that is, the use of solar film as a solar filter can achieve better image quality, and even can easily record the sunspot activity on the surface of the sun. 6、Upgraded Solar Film: The second generation solar film is a film material with bright silver on both sides. In line with the ISO standard solar filter film can protect your eyes when observing the sun, if the solar film appears before the use of light leakage, please stop using immediately. Specification Item Type: Film Solar Filter Weight: 225g/7.9oz Material: Aluminum alloy and PET and aluminum foil Outer Diameter of Frame: 176mm Support Objective Lens Size Range: 144-170mm Aperture: 152mm Package List 1 x Film Solar Filter