The Timney 49er 49 or 90 DEGREE SAFETY (Ambidextrous) can be used in either the normal 90 degree or for ultra quick changes a 49 degree short throw for quick and easy manipulation. In addition, the safety features an end plate allowing the removal of the ambidextrous arm if a one-sided safety is preferred. The 49'r is a true drop-in part that will work with any Mil-Spec lower receiver.