This is a Carl Zeiss Jena M42 mount prime wide-angle lens. It has the zebra pattern characteristic of Jena lenses, and based on the serial number and model designation, it appears to be a Flektogon model that was shipped to Eastern European countries. Despite its large aperture, the lens is designed with a moderate maximum aperture to minimize aberrations and achieve high resolution, allowing you to enjoy its fine detail even in the digital age. The depth of field is not overly sensitive, making it convenient for snapshots. Since there is no M42 mount category, I am using the Sony α series category. I believe you can enjoy sufficient wide-angle photography with both full-frame and Four Thirds cameras. Front and rear lens caps are included. Combined with the mechanical appearance typical of German old lenses, how about taking this lens with you on your everyday walks around town? It will be shipped via Yu-Yu Mercari Bin. Thank you for your consideration. Focal Length...19-70mm Maximum Aperture...2.9-4 Other Features...Old Lens