The Low Ported Barrel Narrow (MB 43LP) Design: Curved mouthpiece with upward and low-ported centre barrel Function: Rolls downwards onto tongue and bars. No palate pressure. With the tongue pressure before tongue relief, the port encourages relaxing at the poll. Does not collapse on the bars nor pinch the tongue. Turns into a solid mouthpiece when asking for a stop. Each side turns independently. offers tongue relief and release when horse relaxes at poll. Less tongue relief than MB 43. Level: Two-Three Usage/Solution for: Like the MB 43, the MB 43LP offers a "Comfort Zone" when the horse is relaxed at the poll. With independent side movement, the MB 43LP works well when lifting a shoulder, bending, collection and stopping. It is a good choice for spoiled horses and those needing encouragement to relax at the poll or lift a shoulder.