Stainless Steel Long Shank Combination Bit - 7 1/2" Shank with Sweet Iron Low Port Comfort Snaffle (MB 04) Copper Inlay Mouth. This mouthpiece is made of polished Sweet Iron which naturally oxidizes. How it works: the long shank combination bit uses five different pressure points to disperse rein pressure. The noseband and chin strap are connected through the purchase; when the reins are engaged, the horse first feels the nose, chin and poll pressure before he feels the mouthpiece. The mouthpiece can slide 1" before reaching the stop, where it will engage. The overall effect is to give the horse several opportunities to respond to the rider’s rein signals, plus disperse the rein pressure over multiple pressure points rather than just the tongue or bars. About the mouthpiece: the 04 mouthpiece is similar to the 02 in that it will rotate on the tongue and apply tongue pressure; however, it has a slight (¼") port that allows the horse to swallow when he is moving forward, relaxed. This port introduces some tongue relief to the horse. The bars of the bit are curved so the bit wraps the bars and lips of the horse’s mouth instead of pinching them when it rotates on to the tongue it. The curve makes more room for the horse’s tongue under the bit. The barrel in the center is the same width as the center piece on a traditional three-piece mouthpiece so applies approximately the same pressure on the tongue. The 04 provides an excellent transition from Level One to Level Two. It’s similar to the 02, but with a ¼" port that introduces tongue relief. Suitable for a wide range of horses: green horses, experienced horses entering the Myler System, horses that have been ridden exclusively in a single-jointed mouthpiece, or re-schooling horses that have not been ridden for a while. Also an excellent schooling bit for horses competing in dressage.