Tamron 500mm f/8 SP 55BB Mirror lens. The lens has good contrasts so it's possible to get very good powerful telephoto shots from this, but like all mirror lenses needs to be used with care, especially on focusing accuracy. It requires a Tamron Adaptall Mount fitting (not included) to attach it to the camera. Mounts were made in most (probably all manual focus camera fittings...so can also be used straight on modern digital Nikon and Pentax cameras via Adaptall 2 mount or Sony/Olympus/Canon with additional converters.
Optics are clean with no scratches, but few specs of dust on inner areas doesn't affect quality.