S&W Model 5900 Series/915 9mm 15rd standard magazines from Mec-gar. Nickel finish. Constructed from certified carbon steel and features a heat treated housing and high-impact polymer or certified carbon steel follower and floorplate. The magazine spring is made of high strength type "D" music wire-the strongest wire available. TIG welding provides additional strength and a seamless finish. Each magazine surface is specially treated to ensure high corrosion resistance.