The Kimblewick - A kimblewick is quite literally a D-ring with a short straight purchase at the top of the D. But uniquely functions as both a direct action and leverage bit using a curb strap. If the rein is attached to the top hook, it works as a direct action bit, exerting the same amount of pressure on the mouth as on the reins. If the rein is attached to the bottom hook, it works like a leverage bit, tilting the mouthpiece forward and applying pressure to the parts of the mouth curb and poll. The Ported Mouthpiece - 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 centre tongue pressure.