This Happy Mouth double jointed loose ring snaffle bit has a unique apple scent that encourages horses to accept the bit and the space age polymer provides for a gentler bit for a happier horse. The center link plastic is a roller to promote acceptance of the bit. The plastic is soft and durable with a reinforcing stainless steel wire inside. Stainless steel cheek rings. 16 mm thickness is Happy Mouth's thin mouthpiece.