This drop-in part is configurable with a reversible selector drum, allowing for either a 45 or 90-degree throw out of the box. Each lever is retained by captured detents, which eliminate the possibility of loosening lever fasteners even during the most demanding firing schedules. Two different lever lengths allow shooters to maintain the benefits of an ambidextrous selector without creating interference for their dominant firing hand during manipulation. | Aero Precision M4E1 PRO Ambi Safety Selector