Shires Sweet Iron Copper Tom Thumb BitWe love this Shires Sweet Iron Copper Tom Thumb Bit because it promotes salivation. With a sweet iron mouthpiece designed to produce a sweet taste and encourage salivation as it oxidizes. The addition of copper ribs helps to prevent the horse from taking too much contact, a good deterrent for horses that tend to take hold. The cheeks give this bit a lever action, creating some poll pressure while the double jointed mouth, with rollers is good for