A pulley can redirect force and multiply it. A simple pulley, consisting of only a single rope, an object, and a fixed pulley, has a mechanical advantage of one and is used only for redirection of force. A movable or compound pulley can multiply force. A movable pulley (right), has a mechanical advantage of 2. This is because you must pull twice the rope that you would have to if you had used a fixed pulley to lift an object to that height. This increase in rope consequently increases the distance which you must pull, therefore decreasing the force required. A compound pulley (below) uses the same technique in only a slightly different fashion. It has all rope movement between two pulleys, still utilizing the increase in rope length, therefore decreasing the force needed.