The Full-Size MTX +5 Magazine Extender by Xtech Tactical is compatible with M&P9 and M&P9 2.0 factory magazines and installs in seconds. Unlike other extenders on the market, the patent-pending design of the MTX permits for a consistent internal wall throughout the extender, which is smaller than the magazine tube. The included spring was engineered specifically for the M&P9 line, allowing for unmatched reliability and last round slide hold open. XTech Tactical's MTX line of extenders are unmatched for reliability, ease of installation, and durability!