Rein connectors attach to the large and smaller rings of curb bits, and the rein attaches to the connector. This gives the rider the same effect without having to hold 2 reins. Our unique Solo rein connectors have holes punched in them so you can choose to make them tighter or looser. This way you can choose which bit/rein has more contact and which one has less, or you can make them equal in length. English leather. Black or brown.