Smith & Wesson M&P Base Pad and Spring Kit 9mm and .40S&W
For High Capacity magazines only.
Will not work for ten round magazines.
Models: M&P 9mm & .40 S&W
Extended Base Pad, add’s 5 rounds in 9mm and 4 rounds in .40
Not for sale in California
Overall length with new base is 140mm
Kit includes extended Base Pad, locking insert and +10% power spring.