Tamron 09NRL 220mm 1:6 lens.  It measures approx. 50mm in diameter across the front, and is screwed onto some form of mount, though looks like it could be removed from this.  I’m not sure if it’s from a projector, or some form of enlarging lens.  It has a red / blue tint to the optics.  There is some internal fungal threading, as per the photos.