This item is a Vivitar Auto f/2.8 135mm TX M42 mount lens.   It is in good condition, average condition for its age and shows signs of use.  The glass is clean and clear.  The focus is smooth.  The aperture is free of oil and works properly.  It has a TX/T4 interchangeable M42 threaded mount.  The TX mount was one of the early industry attempts to make a single lens design that can be used on all of the popular camera mounts in the 1970s.  The Tamron Adaptall was the most popular.  The Vivitar TX and T4 are from this era.  Vivitar is noted for making good quality mid range lenses in this era.