The Pelham has attachments for two reins, one near the mouthpiece and one at the end of the shank or cheek. These reins have similar action to the curb and bridoon reins in the double bridle. Although the combination of both actions on one bit muddy the signals somewhat. However, many horses whose conformation is such that double bridles are uncomfortable for them, go well in Pelhams.
Some riders, not adept at handling two sets of reins, prefer to use roundings, leather loops which connect from one ring to the other on the bit shank. The rein is then attached to this rounding. Obviously, doing this negates the separate actions of the reins, further muddying the signals to the horse.
The Pelham can be further refined with a variety of mouthpieces, such as mullen mouth, low port, etc. to find the most comfortable bit for the horse.