The lens is fully working, standard M42 mount.

The glass is clean, no fungus, scratches, or haze. There might be some dust visible inside against strong light.

The focusing is perfectly smooth with the right amount of resistance - a bit harder than comparable Japanese models but that's normal for these lenses, they used a different kind of grease.

The aperture was modified to work in manual mode - it's always closed down to the selected value, for easy use with any adapter. The modification should be reversible but I can't guarantee perfect functionality without it. 

Visual condition as seen on the photos, comes with the front lens cap - not in the best shape but it's the original one.