Here is a nice bit from Myler in good used condition. Ported correction bits from Myler are one of Myler’s most popular show and training bits. This is an older one, and has rusted, but is in great condition. The sweet iron rusts with use to offer a pleasant taste for your horse. 5″ mouth, 2″ narrow port. MB27, level 2/3. Per Myler:
The MB 27 is a traditional correctional mouthpiece, which has a ported mouthpiece that collapses on to the outer lip and bars, and rotates on to the tongue. This mouthpiece has a 2″. Sweet iron mouthpiece oxidizes and encourages salivation. The 7″ Flat Shank is stainless steel and curved slightly back towards the horse, with a flat-top purchase and a rein ring. The mouthpiece has a fixed attachment. The Flat Shank has the patented Independent Swivel Cheek, where the purchase, mouthpiece and shank all move independently of each other. The purchase is slightly angled away from the cheek to avoid rubbing. It has an indirect (curb) rein action designed to be used with a curb strap which attaches to the purchase. The flat shank uses the combination of the fixed cheek and fixed rein to apply pressure to the mouth, chin and poll.