A curb bit i.e. (Western bit) has shanks, curb bit does not have to be long to put some pressure over the top of the horse’s head and behind the chin, even a bit with two or three-inch shanks is a curb bit. The reins and headstall attach to different rings or slots on the bit. When the reins are pulled back, the bit works on the horse’s mouth, over the top of the head, and under the chin. Curb bit i.e. (Western bit) May have any type of mouthpiece.