 Although some mouthpieces are marketed as "correction" (a euphemism for "severe") bits or "training" (implying a mild bit), the terms are relative.The bit always rests on the sensitive bars of a horse's mouth.A hard-handed rider can make even the mildest bit painful, and a skilled, light-handed rider can ride in a much harsher mouthpiece without damaging the mouth or causing any distress in the horse.