Bob Avila bit. An outstanding bit for an older horse and for any event. It offers just the right amount of tongue relief along with a shorter length shank that seems to be just the right size. This bit has a tremendous amount of feel in a horse's mouth. The copper portions of the mouthpiece are larger in diameter than the port creating a comfortable and balanced feel on the bars of the horses mouth. Port 2", Mouth 5", Shank 7-1/2".