Gag and Elevator Bits
Many novice equestrian riders have the misconception that the gag bit and snaffle bit are two completely different kinds of bits for horses. In fact, the gag bit is a snaffle bit with gag capabilities. That's why it is used with two sets of reins - one for using the bit as a regular snaffle and one to apply a gag action on the horse. If you're looking for entry-level gag bits for horses, the gag elevator bit is a solid and affordable choice.
The gag elevator bit typically has two shanks with a single hoop between them. This hoop is for the snaffle rein. The lower shank usually has a ring to which a gag rein can be attached. Having two reins is important as it allows the rider to employ the bit's gag function on an as-need basis instead of using it all the time. Remember that a gag action is extremely uncomfortable for a horse, so you ought to be circumspect with its use. The gag action is executed with a sliding mouthpiece. When the rider pulls on the gag rein attached to the bit's upper shank, the mouthpiece slides up the bit and places pressure on the horse's mouth. As the gag rein is pulled tight, the bit also applies pressure on the horse's poll, restricting poll flexion. Both of these actions force the horse to raise its head.
There is no getting around the fact that gag elevator bits are a rather severe type of bit. However, when selecting bits for horses, the horse's personality and behavior should be taken into account. If your horse is willful and reckless with a strong tendency to lean into the bit or clamp down on the bit to negate bit control, a severe bit is entirely warranted. By forcing the horse to raise its head, it will prevent such bit-evading behavior. As the horse comes to associate these acts with pain and discomfort, it will eventually shed these bad habits. When that happens, you can begin to slowly make the transition to a full-fledged snaffle bit as the gag function will no longer be necessary. Thus, gag bits are highly recommended for breaking in and schooling stubborn horses, but should not be relied upon in the long-term, especially once your horse has been fully trained. They are not recommended for competitions as their use suggests the rider is not in full control of his horse and may cause the judges to mark the rider down for failing to properly train and discipline his horse prior to the contest.