Premier Equine Mouthing Bit with KeysMouthing bits are commonly used when breaking and training a horse. The keys, also known as players, are designed to encourage the horse to mouth and accept the bit and they can also offer a calming distraction to the horse. Pressure through the mouth does not change very much and the bits action is mainly across the tongue and lips, it does have some pressure on the bars of the mouth depending on the size of the horses tongue. The loose ring