Hanging cheeks help to encourage flexion, whilst the copper lozenge prevents the nutcracker effect of a single joint and encourages salivation. Mouthpiece thickness: 16mm. Cheek height: 110mm. Stainless steel is the most common material for bits. Durable, easy to clean, tasteless and does not rust. Copper is used in the mouthpiece, creating warmth and encouraging salivation to keep the mouth soft.