The ProMag Industries SMI 28 Magazine offers unmatched reliability and durability for firearm enthusiasts. Proudly made in the USA, this magazine is backed by a lifetime guarantee against any manufacturer's defects. With meticulous attention to detail, each magazine features precision-wound springs crafted from heat-treated chrome silicon wire. This ensures consistent performance and longevity. Perfect for those seeking quality and reliability in magazine construction. Heat-Treated Chrome Silicon Wire Spring Manufactured & Assembled in the U.S.A. Easy Loading Rugged Construction Invest in the ProMag SMI 28 Magazine for a reliable shooting experience that stands the test of time.