Experience unparalleled reliability with the ProMag Industries GLK-11 Magazine, crafted for performance and durability. This USA-made magazine is designed to withstand rigorous use and is guaranteed for a lifetime against manufacturer defects. Precision heat-treated chrome silicon wire springs ensure lasting strength and efficiency. Heat-Treated Chrome Silicon Wire Spring Manufactured & Assembled in the U.S.A. Easy Loading Rugged Construction Choose ProMag for excellence in firearm accessories that you can trust.