ProMag SMI31 Smith & Wesson Shield 40 S&W 9-Round Magazine

PROMAG SMI 31, a 9-round magazine for the Smith & Wesson Shield in .40 caliber. Constructed from heat-treated blued-steel, components molded from ProMag rproprietary TECHNAPOLYMER and their anti-fatigue spring, so you can keep the magazine loaded and ready for up to six years without concern. ProMag magazines are made in Phoenix, Arizona and come with a lifetime warranty.