Sway bars are bars that mount between the two front or two rear suspension arms. Usually they are of relatively strong metal. They are "U" shaped with each end of the "U" mounted to each arm. The middle of the "U" is secured to the chassis. If you can envision that, then you will see that if both arms are moving up and down at the same time and same speed, the swaybar doesn't really have any effect. But if one arm tries to move without the other, the stiffness of the swaybar will limit the action on that arm. One big thing it does is limit chassis roll. Helps keep the weight transfer to a minimum. Essentially you'll get much better cornering.