If you are looking to transition up from an o-ring snaffle this 3 piece dog bone bit would be an excellent choice.

4″ Cheeks
5 1/2″ Mouth
5/16″ Twisted Wire
Dogbone
The designated curb ring allows the horse to be introduced to curb pressure under light leverage.
Has a mild gag for bend.
This would be an excellent choice for a beginner to advanced horse and is intended to be used for slow work.
Stage B is all about transition, with the introduction of leverage and curb pressure to help move from direct reining to neck reining. Short shanked bits and half-gags comprise Stage B.

0119-8000 Reinsman Josey-Mitchell Short Stop 3 Piece Dog Bone Bit