The Matador Arms Mag-X Magazine Conversion Kit allows you to use your pistol magazines in any AR-15 milspec lower - the ultimate PCC-pistol combination for Glock users. FeaturesFits any standard AR-15 lower receiver.No modifications required to your lower or magazine.Installs in seconds.Built-in magazine release.Locks into place with the standard AR-15 catch.Lightweight aircraft-grade aluminum construction; anodized finish.Steel ejector and magazine catch. Notes:Only compatible with mil-spec AR-15 lower receivers, combined with a 9mm upper with a Glock-cut bolt.No last round bolt hold open.Hand-fitting may be required with FM-9 uppers.The MagX will not work with the CMMG Radial Delayed Blowback.