This bit can be placed perfectly in the horse's mouth. The horse's tongue gets enough space because of the flattened area on the port. Many horses react to this with more relaxation and chewing. Therefore this bit is perfect for horses that won't tolerate pressure on the tongue and react with head shaking and such.
At the same time this bit is a good choice for horses that like to play with their tongue and get it over the bit. The port will help to prevent that by removing center tongue pressure.