A hollow mouth makes this bit lighter and softer while the two-ring gag offers leverage options to increase severity. The 5" and smaller sizes of this bit have smaller rings to ensure the bit remains proportionate.
Mouthpiece thickness: 21 mm.
Cheek height: 115 mm (4.5", 5"), 145 mm (5.5", 6").
Stainless steel is the most common material for bits Durable, easy to clean, tasteless and non-rusting.