This baseplate is designed for the MecGar P226 or Beretta 92FS, 9mm 18 round or the 40S&W 13 round magazine. This baseplate will convert the standard magazine & allow it to be used with the 3D printed magwells. This model also fits Beretta 17 round magazines to match with our magwells. The CZ75 17 round mags are also compatible with this baseplate. Attention! This baseplate does not fit the Mecgar new style square notch floor plates. Round peg floor plates are required.