Gen 4

6 Adjustable User SettingsStainless Steel (Black Oxide) Washers  The Advanced Adjustable Recoil Reduction System offers 6 Adjustalbe User settings. The included 2 Different Buffer Washers and the 3 Different External Springs can serve Factory and Heavy Ammo. National Tactical Officers Association Tested & Recommended.

 This Unique DPM Mechanical Captured Recoil System is a direct replacement of the factory recoil rod and it doesn't require any configuration before the installation. 

This Unique DPM Mechanical Heavy Duty Captured Recoil System is a direct replacement of the factory recoil rod and it doesn't require any configuration before the installation.   HEAVY DUTY (++P Loads)