This drum magazine is constructed of polymer to ensure a long service life. This AR-15 5.56 model has a 65-round capacity and a black finish.ProMag magazines are designed utilizing modern precision injection molding of Mil-Spec polymer compounds. Every ProMag magazine is backed by a lifetime guarantee against manufacturer's defects. Features: Over molded stamped steel feed lips and magazine catch Magazine body constructed of a proprietary DuPont Zytel based polymer Injection molded follower Magazine spring formed from heat treated chrome silicone wire Made in USA