Herm Sprenger NATHE Mullen Mouth Loose Ring Bit with Copper Link - 20mmWe love this bit because not only is it very soft and bendable in the horse's mouth, but it also features a copper center link to promote proper salivation! Mouth and tongue friendly The copper part fosters the acceptance of the bit Stimulates the flow of saliva Improves the chewing activity of the horse Steady and even pressure on the tongue Bit guards protect the lips Material Thermoplastic Bit size 125 mm, 135 mm, 145 mm Bit thickness 20mm