A double-stack 15-rd magazine for the Smith & Wesson M&P series of pistols in caliber .40S&W. Constructed from heat-treated blued-steel with a follower lock-plate and base-plate molded from a proprietary DuPont Zytel based black polymer; and using a spring wound from Chrome-silicon wire and heat-treated for strength and reliability. Made in the U.S.A.