The S&W DOUBLE-COLUMN 9mm mags fit the Kel-Tec P-11...I don't believe any of the S&W mags fit flush...the 12-shot 6906 mags protrude or hang down a little, but Kel-Tec makes a slip-on "boot" that covers the protruding section of mag and gives a little more "little finger purchase"...the 15-shot 5906 mags "hang down" quite a bit, but all of 'em that I've tried in my P-11 have fed flawlessly. I suppose if one wanted to be totally rediculous, the 20 and 30-round aftermarket mags for the S&W 5906 series would work, but...having that much magazine protrude would SEEM to defeat the purpose of having the SMALL Kel-Tec in the first place, yes???....mikey357