If you need to lower your saddles more, but the screw head is touching the string and preventing you from lowering it any further, you need this flat top screw and shorter saddle riser #8320 for each saddle you want to lower. This flat head screw will allow you to lower the saddle to a point lower than the factory setting. FYI: The taller stock screw does double duty by preventing you from lowering the saddles too far, thus causing the dreaded "citar effect". On some guitars you can get away with it depending on how the bridge is setup, Strat's and Telecasters for example, may work out of the box "as is", but on other guitars, you may experience "rattling roller syndrome". If that happens you need to raise the saddle until the rattling stops. Uses a Phillips screwdriver.