Bridle Double

A double bridle or Weymouth bridle is a piece of horse tack. The bridle is used with two bits and two reins. One rein, the bradoon, is a modified snaffle bit, and it sits above the other bit used in a double bridle, the curb bit.

Double bridles, originally called "full bridles," were much more common several hundred years ago. Considered the "proper" equipment for a trained rider and horse, a simple snaffle bridle was only for green horses and riders, young children, grooms, and poor riders. Riders today, especially juniors and amateurs, tend to prefer the snaffle bridle for basic work. However, many hot horses go much better in a double bridle, and it can also be helpful on rearers.

The snaffle rein (attached to the bradoon), should be thicker than the curb rein, so that the two are easily distinguished by feel. The snaffle rein should also be kept slightly shorter than the curb rein, and should be used to give the majority of aids. The curb rein only comes into play when needed.

Double bridles are fairly common for showing purposes in the United Kingdom, but are very rarely seen at shows in the United States, except when used in Saddleseat competition. Double bridles are required for the FEI dressage tests (PSG, Intermediate Level, and Grand Prix), and are optional at the USDF third and fourth level. They are also permitted in the dressage phase of eventing, at the Intermediate or Advanced levels, although not required.

source