Basic concepts to remember when selecting a bit:
• Mouthpieces can be made of different types of metals, hard rubber or flexible rubber. Each yields a different effect.
• The thicker the mouthpiece the milder the bit, because the bit pressure is spread over a larger area. The thinner the mouth piece, the more severe the bit.
• The length of the shank dictates the amount of curb pressure and leverage or pressure applied to the chin groove and the poll of the horse.
• There are various mouthpiece configurations. Each mouthpiece helps to determine the function of a bit. See mouthpiece descriptions for additional explanation.