The Reinsman Freter Butterfly is excellent for introducing curb pressure to a young horse advancing in their training. The gag action of bit encourages softness and promotes forgiveness in the riders hands, allowing for a slight delay in reaction when the horse receives cues from the rider. The smooth mullen with the low port mouthpiece encourages the horse to square up their shoulders and work towards vertical collection without getting heavy in the bridle and front end. Lifetime warranty.