This double jointed Dee-Ring bit is made of solid German stainless steel combined with a layer of sweet iron on the mouthpiece (blue). The sweet iron stimulates the chewing process and saliva formation. When this material reacts with moisture, warmth and air in a process called oxidation, the surface rust tastes sweet. As a result, the horse will be more willing to accept the bit. The blue colour disappears eventually, but the taste of the surface rust remains.