NOT JUST A BIT - It's a Patented adjustable mouth bit!! Brand New design! This training wide port bit offers a lot of tongue release . Two reins can be used if necessary or use as a direct rein bit from the center ring. The shanks are slightly bent to the rear which slows the action of this Adjusta bit. No more mistakes in buying the wrong size, less to have hanging around on your tack room wall. This innovative new bit adjusts to precisely fit any size mouth from 4-1/2 to 5 1/2. Simply twist the shanks in opposite directions and the bit size increases or decreases. No tools required. A simple concept that works.