Reinsman Just Enough Bit. 5 1/2" cheeks, 5 1/2" mouth. Sweet and sour mouthpiece with lifesaver. 
 
"Nice transition bit when moving from the ring snaffle to a curb bit. Limited gag action is softer than moving from the ring snaffle directly into a curb bit with swivel or solid cheeks. The 3-piece mouth results in soft and even pressure across the tongue, bars and lips. Sweet and sour combination mouth increases salivation to lead to  a more relaxed jaw and supple mouth."