The plate in the middle swivels about 60 degrees up and about 20 degrees down with a stop so it cannot rotate all the way around the mouthpiece. This tongue grid is to help with one that has a habit of flipping its tongue over the bit, but does not like a tall port for the same purpose. This mouthpiece is better than a rubber tongue port that breaks or slides to one side and the rubber ports really only work on a single jointed mouth piece. Since the bit has joints you do not loose the control that comes from ported bar type bits. As with all these mouthpieces, they can be done in Loose Ring, Pelham, and D Ring bits, sized 5? and 5.5?. Full cheeks are the standard style.
Made in Britain