This is the Summicron 50mm, often called Leica's standard lens. I used it frequently, so there is some wear, but the lens itself is in good condition. It has been stored in a dehumidified storage. Based on the serial number, it originally did not have 6-bit coding and was likely modified later. This high-performance 50mm prime lens with a maximum aperture of f/2 delivers excellent image quality even in low light. - Model Name: SUMMICRON-M 1:2/50 - Focal Length: 50mm - Maximum Aperture: f/2 - Minimum Focusing Distance: 0.7m - Lens Construction: 6 elements in 6 groups Thank you for looking.