Hanging cheeks help to encourage flexion, whilst the lozenge prevents the nutcracker effect of a single joint. Mouthpiece thickness: 14mm. Cheek height: 110mm. 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.