The Endomag system does NOT come with a PMag. You must either add on one to your order or use a Gen 2 or 3 PMag that you already have
The MEAN EndoMag® is a magazine insert that converts your Gen 2 or Gen 3 5.56/.223 PMAG® housing into a 9mm magazine to use with a standard AR lower and 9mm upper with a Glock or Colt variant 9mm BCG.
EndoMag features: