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. It is precision machined, heat-treated steel, with replacement spring and carbo nitride coated safety plunger for ultra-smooth operation with extremely positive engagement. Features: Fast, ergonomic 49-degree throw for lighting fast safety manipulation Superior coatings for best-in-class fit and feel Precision-machined surfaces for smooth operation in any environment Made in the USA