DPM Government 5in Barrel / Clones Bushing Only Mechanical Recoil Reduction System Black Oxide. The third spring which is contained within the rod controls the movement of the slide so it never rams on the frame. The system includes 1 spring plug and 3 different external springs. The spring plug must always be installed when the DPM Recoil Rod and springs are used. The external springs are different in length the long spring is heavy and the short is light so the shooter can fine tune the pistol on the opening and locking positions (slide on the battery). As we lead the evolution of recoil reduction technology products may change versions (new design with different springs with or without plugs washers etc.) without any prior notice. Specifications for DPM 1911 Government 5in Barrel / Clones Bushing Only Mechanical Recoil Reduction System: Manufacturer: DPM Fabric/Material: Spring Steel Gun Make: 1911 Platform Gun Model: 1911 Government Package Contents: DPM 1911 Government 5in Barrel / Clones Bushing Only Mechanical Recoil Reduction System What firearm models does the manufacturer say DPM 1911 Government 5in Barrel / Clones Bushing Only Mechanical Recoil Reduction System is compatible with? The manufacturer says that DPM 1911 Government 5in Barrel / Clones Bushing Only Mechanical Recoil Reduction System is compatible with 1911 GovernmentDPM MS-1911/A1-5-SE: 1911 Government 5in Barrel / Clones Bushing Only Mechanical Recoil Reduction System Black Oxide