Bucking rolls are a piece of equipment sometimes added to the front of a saddle. They act as a supplement to the saddle's swells to help the rider stay in the saddle when a horse is bucking or during other rough riding. They can be used on most any style of Western saddle but are most commonly found on ranch saddles. 

Bucking rolls are designed to be easily put on or removed. On Western saddles there are typically two screws toward the front of the saddle  that are simply unscrewed, then the bucking rolls are put into place and the screws are put back in. Conchos and/or saddle strings can be used in place of the screws.