Designed as a replacement or spare magazine the Promag Standard Pro Smi31 Mag Shield 40sw 9rd Steel provides 9-round capacity for 40 S&W. It features Steel construction. It is intended for S&W M&P Shield compatibility.It is a straightforward choice for replacing a worn magazine or keeping an additional magazine available for range training or field use.Caliber: 40 S&WCapacity: 9 roundsMaterial: SteelFit: S&W M&P Shield