Curb Bit 18th century German This driving bit was used for horses pulling carriages and sleighs. The large rings prevent the bit from pulling through the horse's mouth. The triangular loops on the purchases attached the bearing reins, connected to the horse's collar. They were used to prevent the animal from lowering its head, and, for aesthetic reasons, to adjust all the horses' heads to the same level.Driving bits are usually more rigid compared to riding ones, as the voice and the hand are the only ways of communicating with the animal.. Curb Bit. German. 18th century. Iron alloy. Equestrian Equipment-Bits