Scientific design: K9 prism with higher refractive index is used to make the imaging clearer, the picture brighter and the colors more vivid. The high-definition field of view from the broadband coating has an average transmittance of 99.5% in the spectral range of 400 nm to 600 nm. It also has anti-distortion design, which can achieve high color reproduction, so that your recorded landscape is always in front of your eyes. Anti-distortion: This telephoto lens has a new anti-distortion design. The anti-distortion telephoto lens can effectively eliminate the image of the object and its surroundings produced during telephoto shooting. And this lens has high color reproduction. It can also focus precisely and clearly. For different distances, rotate the focus ring to the left and right to get accurate focus. Light : This TX-13 telephoto lens adopts and aluminum alloy body, and the environmental high-grade rubber is non-slip processing. It uses FMC coating and multi-layer coatings on lenses and prisms to improve light , up to 98.5%. Ultra portable: This telephoto lens has a 37mm threaded interface and is suitable for 37mm fixed focus digital cameras and mobile phones.It is suitable for travel, concerts, ball games, bird watching, etc. Even if you cannot buy a SLR camera, you can use this lens to record these wonderful moments with your mobile phone more clearly. Portable size, for indoor & outdoor use.Can record your life on the . TX-13 telephoto lens with and aluminum alloy body, environmental high-grade rubber for anti-skid treatment. FMC coating is adopted, and multi-layer coating is applied to lens and prism, so as to enhance light transmittance, which is up to 98.5%. The prism adopts the K9 prism with a higher refractive index to make the imaging clearer. With 37mm thread interface, suitable for 37mm fixed focus digital camera and mobile phone.