ProMag Industries Magazine, 223 REM/556NATO, 10 Rounds, Roller Follower, Fits AR-15, Polymer, Matte Finish, Black RM-10 ProMag magazines are made in the USA and backed by a lifetime guarantee against manufacturer's defects. The ani-tilt Roller Follower provides maximum friction reduction. Magazine springs are precision wound using heat-treated chrome silicon wire and each and every step of the assembly process is checked and double checked in order to maintain the same consistent level of quality.