It comes with 5 magazines total, which is 3 more than they come with new. Two of the mags have the sig +2 extension on them that brings them to 12 round capacity, two of the magazines have the +3 base plate extenders giving them 15 round capacity, and one magazine has the the flush/factory base plate for 10 round capacity. The two original base plates are included if you want to run factory spec.