times been Americanized as "McCarty" or "McCarthy" and "Theodore," but such usage is considered incorrect by hackamore reinsmen of the American West. The bosal acts on the horse's nose and jaw, and is most commonly used to start young horses under saddle in the Vaquero tradition of the "California style" cowboy. The bosal is a very sophisticated and versatile style of hackamore. Bosals come in varying diameters and weights, allowing a more skilled horse to "graduate" into ever lighter equipment. Once a young horse is solidly trained with a bosal, a bit can be added and the horse is gradually shifted from the hackamore to a bit. While designed to be gentle, Bosals are equipment intended for use by experienced trainers, as they can be confusing in the wrong hands. The bosal acts as a signal device providing a pre-signal to the horse by the lifting of the heel knot off the chin when the rider picks up on a rein. This gives the horse time to be prepared for the impending cue. Hackamores are traditionally used one rein at a time, with fluctuating pressure. Pulling back on both reins with steady pressure teaches a horse to brace and resist, which is the opposite of the hackamore's intention. Hackamores are used in the classic Vaquero tradition to teach young horses softness, and to give readily to pressure while leaving the mouth untouched for the spade bit later on in training. Bosals come in varying diameters and weights, allowing a more skilled horse to "graduate" into ever lighter equipment. Once a young horse is solidly trained with a bosal, a spade bit is added and the horse is gradually shifted from the hackamore to a bit, to create a finished bridle horse. Some horses are never transitioned to a bitted bridle, and it is possible to use the hackamore for the life of the horse. Sidepulls The sidepull is a modern design inspired by the bosal, though it is not a true hackamore. It is a heavy noseband with rings that attach the reins on either side of the head, allowing very direct pressure to be applied from side to side. The noseband is made of leather, rawhide, or rope with a leather or synthetic strap under the jaw, held on by a leather or synthetic headstall. Sidepulls are primarily used to start young horses or on horses that cannot carry