Stripped, semi-auto, billet upper receiver. Perfect platform for building your unique, mission-specific, AR-15 pistol caliber rifle/pistol. Made from a high-strength, 7075 T6 aluminum for durability. Mil-Spec, MIL-A-8625 Type III hard-coat anodized finish adds extra strength and delivers superior abrasion-resistance for rugged field use. Precision-machined to ensure drop-in installation of Mil-Spec, aftermarket components.