The MB 04 is similar to the MB 02 in that it will rotate on the tongue
and apply tongue pressure, however, it has a small (¼") port that
introduces some tongue relief to the horse. The port allows the horse to
swallow and move his tongue when he is moving forward and relaxed,
which acts as a release or reward. The mouthpiece is curved, and it
wraps around the bars and lips instead of pinching. Sweet iron
mouthpiece oxidizes and encourages salivation.
The MBB shank is a length of flat black steel curved slightly back
towards the horse, with a teardrop purchase and a rein ring. The
mouthpiece has a fixed attachment to the cheek with a decorative
“stack.” The shank is decorated with stainless steel dots. The purchase
is angled slightly away from the cheek to avoid rubbing. The black steel
will discolor over time to an antique brown.