The EquiKind apple flavoured mouthpiece on this bit makes it more comfortable in the horse?s mouth. The three rings cheeks allow leverage. The 5" and smaller sizes of this bit have smaller rings to ensure the bit remains in proportion. Mouthpiece thickness: 18mm. Cheek height: 150mm (4.5", 5"), 180mm (5.5"). The EquiKind mouthpiece has the benefit of being lighter and more flexible. Particularly suitable for young, sensitive horses as they are kind on the mouth. The apple flavour makes them palatable and therefore easily accepted. Stainless steel is used due to it being durable, easy to clean and resistance to rust.