This is the ProMag Smith & Wesson M&P .40 S&W 50-round drum magazine. 

Spend more time shooting and less time reloading with this high-quality 50-round drum magazine from ProMag! 

Designed for maximum durability, ProMag opted for a steel upper magazine tower and a DuPont Zytel based polymer drum. You’ll be hard pressed to find a tougher drum mag. 

Reliability will never be a concern either, thanks to the injection-molded polymer follower and heat-treated stainless steel spring. Add to that the fact that ProMag backs each of its magazines with a lifetime warranty, and there is not much else you could ask for! 

Stay locked and loaded by ordering one of these 50-round drums today!