Caliber/Gauge
40 SW
Introducing the new PROMAG® SMI 31, a 9-round magazine for the Smith & Wesson® Shield® in .40 caliber. Constructed from heat-treated blued-steel, components molded from ourproprietary TECHNAPOLYMER® and our anti-fatigue spring, so you can keep the magazineloaded and ready for up to six years without concern.
