The loose ring has much more movement and play than a fixed ring or cheek. It discourages fixing, blocking, and leaning on the bit. It also helps to encourage mouthing. The loose ring allows more movement so that it follows the angle of the tongue, this is vital because as the horse's overall outline changes it allows the bit to follow. Breaking bits with keys are usually used for starting young horses to encourage them to mouth. The keys are movable and this encourages them to accept the bit in the mouth