Stainless Steel 3-Ring Combination Bit – 6? Shank with Sweet Iron Mullen Triple Barrel (MB 32-3, Level 2) Copper Inlay. This mouthpiece is made of polished Sweet Iron which naturally oxidizes or rusts. Harmless to horses, it has a sweet taste and promotes salivation. Now comes with black leather noseband and synthetic black curb strap (not as pictured).