With the Warne Magazine Extension for Smith & Wesson M&P 9/40, the addition of firepower will serve you will on and off the field, giving you the option to continue shooting even after you would have originally run out of ammunition. The ergonomic shape gives you better insertion and the ability to strip the handgun from the magazine if needed. It has been made specifically to fit the Smith & Wesson M&P factory magazines with a capacity of +5 9mm and +4 .40. The red color gives a sleek look that will seamlessly blend with the existing magazine.