The Tom Thumb bit is a cross between an American gag and an elevator bit. It offers more precision and control and is very popular for show jumping and cross country. It has a lifting action in the front that can help the rider sit the horse on its hocks, allowing for tighter turns and more efficient jumps. The lifting action combined with tail pressure can also discourage horses from leaning on the bit. It can be used with a single rein on the snaffle ring or lower ring or, for greater precision, with two reins. The diamond in the center of this bit conforms to the shape of the tongue and helps reduce the nutcracker effect of a single-jointed bit, which helps create a soft contact, allowing for clear rein aids. Copper is a warm metal that encourages salivation and biting on the bit. A useful bit for horses that tend to lean on the rider's hands. MeasurementsAccording to our size guide, the A and B measurements of this bit are:A=16mmB=135mm Stainless steel horsebit...Stainless steel is...