Timney 49ER Ambidextrous Safety fits AR15- The Timney 49er is a 49 or 90 degree AR15 safety (Ambidextrous). It 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 comes 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.- It is precision machined, heat-treated steel, with replacement spring and carbo nitride coated safety plunger for ultra-smooth operation with extremely positive engagement.Benefits