The Noveske STS is an ambidextrous safety for your AR-15 that has a shorter 60 degree range between Safe and Fire; this is 30 degrees shorter than the standard safety. The Short Throw Selector (STS) is constructed with a stainless steel nitride selector drum and molded levers from MagPul Industries. Installation of this selector requires a very small Jewelers flat blade screw driver (not included).