Cambridge Mouth Kimblewick with Slotted Rings. The Cambridge Mouth Kimblewick is a stainless steel bit with a port that allows extra room for the tongue whilst retaining the straight bar action; the bit is ideal for horses with a big tongue or a small mouth. The Cambridge Mouth has a straight mouthpiece that offers a more consistent action and acts on the tongue and the bars of the mouth. The Kimblewick combines the action of a curb rein with a snaffle bit yet is more severe than other snaffle bits as it has a leverage action on the jaw which helps to give the rider more control. Read more… The Cambridge Mouth Kimblewick should be used with a curb chain which applies pressure to the chin groove for added control.