This curb is a step up from the flat chain. The chain has a twist, so it creates an uneven contract on the jaw. This is designed to ask the horse to extend its poll forward which helps with anatomical balance front to back. The higher the curb sits up the jaw, the clearer the signal will be for the horse to go forward into the bridle. Excessive contact and delayed release can cause a horse to stay behind the bridle. The horse should be in your hands, not pushing or avoiding the bit, which takes time, patience and practice. This curb is available in 3 ½” and 4 ½”.