Industar-50U List of brands that produced cameras that can be used with a lens with an M39 thread (Leica thread):
Leica: Leica M-system cameras such as Leica M2, M3, M6 and others use lenses with M39 thread.
Voigtländer: Some Voigtländer camera models, such as the Bessa R and Bessa L, are also compatible with M39 lenses.
Minolta: Some Minolta cameras, such as the Minolta CLE, have an M39 thread and can accept suitable lenses.
Canon: A number of Canon cameras, such as Canon IV, Canon VT, Canon P, also use lenses with M39 thread.
Nikon: Several Nikon models, such as Nikon S and Nikon SP, have the ability to use lenses with M39 threads.
Contax / Zeiss Ikon: Some Contax and Zeiss Ikon camera models are also compatible with M39 lenses.
Ricoh: The Ricoh 500G and 500GX cameras also use lenses with M39 threads.
Konica: Some older Konica models, such as the Konica III and Konica IIIA, can also accept lenses with M39 threads

And also many other cameras

Specifications:

Focal length: 50 mm.
Maximum aperture: f/3.5.
Minimum aperture: Not specified.
Optical design: 4 elements.
Mounting type: Originally designed for photographic enlargers, but can be adapted for use with modern cameras via appropriate adapters.
Focus: Manual.
Minimum focusing distance: Approximately 30 cm.
Weight: About 65 grams.
History and Origin:
The I50U lens was produced at various optical factories in the USSR. It was popular among photographers for its sharpness and image quality, especially in macro photography.

📦 Equipment:
Lens "I50U" 50mm f/3.5.
Lens cap (if equipped).

🚚 Delivery:
International delivery with track and trace.
Delivery times may vary.

🔒 Safe Payment:
Payment through eBay's secure payment system.

📩 Contact the seller:
If you have questions about I50U or would like to know more, please contact me.