This specific DPM Mechanical Recoil System it is based on the DPM Patent Multi-spring Recoil Reduction System and functions due to the multi spring intricate rod (3 springs). 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 3 different in length Washers, a Compressive Disc, a Safety Pin and 3 different in power External Springs. The longer Washer offers a heavy buffer effect, moving to shorter Washer a lighter buffer effect is being offered. The external springs are different in length, the long Spring is heavy and moving to Shorter is lighter so the shooter can fine tune the pistol on the opening and locking position (slide on the battery) according his/hers personal standards. Specifications for DPM Adjustable Multi-Springs Glock Gen 5 Mechanical Recoil Reduction System: Manufacturer: DPM Color: Stainless Fabric/Material: Stainess Steel Gun Make: Glock Gun Model: Glock 35, Glock 34, Glock 22, Glock 17, Glock 37, Glock 31 Features of DPM Adjustable Multi-Springs Glock Gen 5 Mechanical Recoil Reduction System 9 Adjustable User Settings Black Oxide Stainless Steel (BOSS) Package Contents: DPM Adjustable Multi-Springs Glock Gen 5 Mechanical Recoil Reduction System