Kimberwick English Bits
This type of bit is named after the town in which it was originally founded, Kimberwick, England. Due to the purchase arm and geometry of the rings, the rings may function as very short lever arms and create a small amount of leverage, which puts this type of bit into the Pelham or curb bit "family." This bit can have so many different functions depending on a rider's hand position if the Kimberwick has slots to hold the reins in place.
The original design has a ported mouthpiece, and now it is also manufactured with others, including a solid, un-jointed "mullen" mouth, and a single-jointed mouthpiece. The difference in mouthpieces affects its severity. Used correctly the Kimberwick can be quite effective but in the wrong hands can be extremely harmful to not just the horse's mouth but also making a horse invert due to the direct force upon the horse's face and chin.