Clean Schneider Kreuznach blue window 135mm f/5.6 Componon-S enlarging lens with factory caps. Does not have a retaining ring. The glass is clear with no fungus or haze. The aperture ring turns smoothly. The lens is clean cosmetically. 50mm X .75 thread mount. Appropriate for negatives up to 4x5 inches. These are one of the sharpest lenses out there and this is really fine example.