Replacement springs
I purchased these springs as a replacement for the weak springs that came with my magazine extensions. The extensions are fine, just the springs are weak. These Taran Tactical springs are great. I tested one in my M&P 9mm and it worked flawlessly. I am trying another of the 6 I purchased in my M&P 40 extended magazine. A dry run shows it will work also. I will purchase more springs next year.