For me, the Leica M2 camera is the benchmark. At the same time, if we are talking about lenses, it must be admitted that  Leica has also created excellent working tools. 

But like all artists, the photographer deserves something more.
I'm pretty successful in pairing an excellent camera with unique lenses.
 
Dear Leica M camera owner!
I'm happy to offer you a bid on an excellent condition, customized, full frame, 15-blade aperture, and rangefinder coupled to a Leica M camera.

 UNIQUE XENON 1:1.9 40mm lens

This is an original vintage Double-Gauss scheme XENON 1:1.9 f=40mm lens from the famous German SCHNEIDER-KREUZNACH brand. The barrel and aperture were customized and adapted to any Leica M-mounting and mirrorless cameras. 


The rangefinder of any Leica M(1, 2, 3, 4, 4-P, 5, 6, 7, 8, 9, 10, CL, type 240, MP, etc.) cameras will fully work with the lens. Of course, any other cameras with Leica M mounting or an appropriate adapter will also work with the lens.
 
The stopper ball was removed at the request of the video-filming fans. The aperture ring rotates smoothly without clicks.

All customization works were performed in my associated workshop by a high-level professional.

The optical performance of this lens is 10. The glass is free of haze and fungus, has no dents, and is as clear as much as an 80-year-old lens can be. Operational micro-scratches and small dust particles are possible without obstructing the image. Zoom movement is smooth, and the aperture adjustment ring mechanism is concise—no scratches, bashes, or dings of the barrel. Please study the high-definition photos closely to evaluate the condition, as they are essential to the description.

The lens will be shipped by registered airmail. The winning bidder receives free tracking and insurance.

Please see my other items.
If you're not satisfied with this lens, I will gladly accept a return within 14 days after delivery at the buyer's shipping expense.

Although I try to describe my items accurately, it is sometimes possible to omit or overlook points that may seem unimportant to me but very important to you. I urge bidders to ask questions first, not after the auction ends!
Please leave me feedback on eBay if you are happy with my service
.. 
If you are unhappy, please let me know first so I can sort out any issues.

GOOD LUCK WITH THE BIDDING!