Professional's ChoiceSmooth Dogbone Bit3in D Rings5-1/4in MouthSweet Iron w/Copper InlaysEQB-810 Made of sweet iron with copper inlays, keep the horse's mouth soft and moist. This bit works well for green or sensitive horses. 3in rings and 5-1/2in mouth. This bit will rust when exposed to moisture. This creates a sweet taste in the horse's mouth and promotes salivation.