This bit is often used to help with control. The double joint with lozenge softens the nutcracker action and the brass alloy assists with salivation. Can be used with double reins or Pelham roundings. Mouthpiece thickness: 14mm. Cheek height: 115mm (4.5"), 130mm (5"), 140mm (5.5", 6"). Brass alloy mouth: Copper is alloyed with a harder metal to produce warm, durable mouthpieces which aid salivation. Stainless steel is used for the cheeks due to it being durable, easy to clean and resistance to rust.