Description These magazines were designed for professional shooters and law enforcement personnel whose lives depend on a perfect shot every time. Expertly machined for exceptional quality and guaranteed to feed and function for every shot. ProMag magazines include a lifetime guarantee, if you ever have a problem with their magazines; simply return them to ProMag for replacement. When you need a cost effective aftermarket replacement mag that you know you can count on, you need a ProMag!PRODUCT DETAILS:Manufacturer Number: COL-A18B Promag AR-15 Magazine Caliber: .223 Remington, 5.56 NATO Capacity: 30 Rounds Body Material: Dupont Zytel Polymer Spring Material: Chrome Silicon Wire Follower Material: Dupont Zytel Polymer Baseplate Material: Dupont Zytel Polymer Lifetime Warranty Made in the U.S.A. Finish: BlackFits: Colt AR-15 and similar firearms