A snaffle bit, also called a ring snaffle, is made up of a mouthpiece and rings. Snaffle bit mouthpieces are most commonly jointed in the middle. Consequently, curb bits with jointed mouthpieces may also be termed a snaffle, although the bits actually work by leverage or curb pressure. True snaffles are constructed so the bridle headstall and reins are attached to rings positioned on the outside of the horse’s mouth. Snaffles apply rein pressure directly to the mouthpiece, and the amount of rein pressure applied to contact points of the mouth is equal to the degree of pressure applied by the reins. Snaffle bits place pressure on the tongue, the corners of the mouth, and the bars of the mouth.
The picture in the right is an O-ring snaffle. Ring snaffles apply direct pressure from the reins to the horse's mouth. Most ring snaffles have jointed mouthpieces to intensify the pressure on the corners of the horse's mouth. This enhances the ability to pull laterally, thus directly guiding movement by repositioning the horse's head to the direction of desired movement. Pressure is intensified by using multiple mouthpieces, small diameter mouthpieces, or rolling or twisting mouthpieces.
Inexperienced horses are taught to respond from a direct pull of the reins. Young or inexperienced horses are expected to require frequent reinforcements following the horse's response to an initial cue. Snaffles apply a simple type of direct pressure when used correctly and are mild enough to use with frequent reinforcements. English style riding allows for continual snaffle use throughout the use of the horse, as these horses are ridden with a constant, light contact. Most Western showing requires that older horses perform in curb bits. Even so, snaffles are commonly used as a training tool throughout the life of horses ridden Western style because of the advantages of snaffle action when applying frequent reinforcements or when conducting riding activities that require constant slight mouth pressure.