Mass Driver Comp for GEN5 GlockPackage Contents:-x1 Comp main body-x1 Recoil spring-x1 Guide rod-x1 Guide rod fitment washer-x1 Guide rod head-x1 Internal spring-x1 Guide rod plug (GEN4 only)-x1 Warning cardProduct Features:-No threaded barrel needed (but can be used)-Eliminates the need for threaded barrels. 50 State Legal-Widened bore to reduce baffle strikes and keyholing rounds-2.5mm relief cut at the top rear of comp to reduce lipping and damage to the face of the slide-No permanent modification of weapon required-Blended, no snag profile-Matches with width of the slide, it can be used with open holsters, no special holster needed-Counter recoil design, as the slide moves back the comp moves forward to reduce felt recoil-Contours with slide dimensions to be compatible with most open-bottom holsters-Precision CNC machinedThreaded Barrels: We recommend use with non-threaded barrels if possible but yes, the Mass Driver Comp is compatible with most GLOCK aftermarket threaded barrels. We've tested with majority of the popular brands on the market such as: AlphaWolf, Battle Arms Development, Bear Creek Arsenal, Brownells, CMC Triggers, Faxon Firearms, Fortis Manufacturing, Grey Ghost Precision, Killer Innovations, LANTAC, Lone Wolf Distributors, Next Level Armament, Shadow Systems, Suarez International, Tactical Kinetics, ZEV Technologies.