If you are changing your timing belt, you may not need this tool. If your old belt is still intact, ie. - no teeth missing, then just mark a tooth on each pulley(2 cam pullies and 1 crank pulley) and mark the corresponding tooth/notch on the belt. Remove the belt and mark the exact spots on the new belt and install. You may need another person to hold the cam pullies in place while you install the belt, but this is easy to do for two people. With this method valve cover removal is not necessary.