Instant purchase welcome. This is an Olympus M42 mount lens. It's a full-frame lens, not for half-frame cameras. The lens was quickly changed to the OM mount, so M42 mount lenses are rare and scarce. [Appearance] There are no noticeable scratches or dirt on the exterior. Please check the photos. [Optics] There is some minor dust, but no mold or fogging, and the optics are relatively good. [Operation] The aperture and helicoid movements are smooth and there are no problems. [Included Items] Front and rear caps are included. [Other] It is listed under K-mount because there is no M42 mount category, but it is actually an M42 mount. #OLYMPUS #Olympus #Zuiko #FTL #Rare #Valuable