The Williams cheekpiece allows for multiple rein positions. If connected to the main ring the bit acts as a loose ring, but when connected to the bottom ring it promotes pole flexion by creating more positive poll pressure. The Williams cheekpiece helps to prevent drifting.

A conventional Snaffle joint has a nut cracker action, which means it will bear pressure on the horse's bars and the tongue. The Barrel joint limits the nut cracker action and spreads the usual pressure over a larger area. When the rein is used this mouthpiece wraps across the tongue creating tongue pressure and taking pressure off the bars due to the lock up action.