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. Be aware that the single jointed mouthpiece may cause discomfort from nutcracker action on the palate.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.