It's a Leica M mount. The mount sustained a drop impact once, and when I sent it in for repair, the artificial ruby was changed to a regular red dot (they said the artificial ruby was no longer available). I've used it about twice since it came back from the repair. At that time, I also requested them to check the operation and optics, so I think it's in very clean and good condition. The lens itself seems to be in very clean condition. There is some wear and tear on the gap. I will add photos if you need any. I'm selling it because I use other 35mm lenses and don't have a chance to use this one. Also known as: Zhou Eight Blades •Included: Original front and rear caps Original lens case Lens body Instruction manual? Box