Para made hi cap mags for both 9 m.m. and 38 Super. The 9 m.m. are 18 rounds and the 38 are 20. These mags are interchangeable. Seems that available mags are the 38's. If the last round in the 38 mag jams the follower low so the round won't feed, it will require a very small amount of material removed from the side of the follower. If you get ay & this happens, post & I'll try to draw the follower & explain what to remove.