The Myler Level 3 MBL Short Shank Sweet Iron Ported Barrel Bit features stainless steel 5 1/2" MBL short shanks with sweet iron wide ported barrel (MB 33, Level 3) mouth with 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.