Bitless bridles work through exerting pressure on the horse's nose.
Snaffle bridles apply pressure on the corners of the mouth, and unjointed snaffles also apply pressure on the horse's tongue. Rollers on the bit may be helpful for young horses who are easily distracted or for horses who tend to lean on the bit.
Double bridles have both a curb bit and a bradoon/Weymouth bit. Curb bits exert pressure on the poll and the bars of the mouth. Pressure on the poll encourages the horse to lower his/her head. Curb bits with long lower shanks (the metal bars extending from the corners of the mouth to the reins) are more severe than curb bits with short lower shanks. The bradoon bit encourages the horse to raise his/her head slightly. Pelham bits offer results similar to the true double bridle. A pelham bit is similar to a curb bit, but a second set of reins attaches near the corners of the horse's mouth.
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