This stainless steel bit is useful when control is an issue - the three rings offer leverage options to increase the severity. The 5" and smaller sizes of this bit have smaller rings to ensure the bit remains in proportion. Mouthpiece thickness: 21mm. Cheek height: 160mm (4.5", 5"), 180mm (5.5", 6"). Stainless steel is the most common material for bits. Durable, easy to clean, tasteless and does not rust.