The mount is L-mount. This lens is popular as one of the three most characteristic lenses in Leica's history. This particular unit is a very early type, made in 1950. The Summarit is known for its front element being prone to scratches, but this unit has been re-polished by the famous Yamazaki Kogaku, so it is in very clean condition. There are no noticeable dents or scratches on the lens barrel, and the operation is smooth. At wide open aperture, it has a unique blur and soft depiction, but when stopped down, it becomes very sharp, allowing you to enjoy the images of the time. There is a slight play in the aperture ring, and the infinity focus is slightly under, but neither of these issues are significant enough to affect shooting. If you are concerned, you may want to have it serviced. Accessories include a filter, front and rear caps, and an L-M ring. A receipt from Yamazaki Kogaku is also included. Although it is in good condition, it is an old lens, so please understand that it is non-refundable and non-returnable.