Meyer Optik Domiplan 30mm F3.5 M39 Mount. Modified 3D printed M39 mount. Glass looks clean with no issues. Lens originally for 1/2 frame 35mm film camera. So it only works on APS-C cameras. Lens is good condition considering it's a 60+ year old lens. Any questions or concerns please message me before buying/bidding. Please refer at the pictures for condition of lens. Both focus and aperture work fine on this lens. Lens was modified to fit 3D printed mount.