DPM Mechanical Recol Gens 1-3 Reduction System Glock 17L/24C/34/35 Stainless. The third spring which is contained within the rod controls the movement of the slide so it never rams on the frame. Also included with the system are 2 separate springs so the user can fine-tune the weapon for his/hers personal standards.The longer spring (more coils) is stronger and has a heavier pound rating than the shorter spring. Specifications for DPM Mechanical Recol Gens 1-3 Reduction System: Manufacturer: DPM Color: Stainless Fabric/Material: Stainess Steel Gun Make: Glock Model Generation: 3 2 1 Condition: New Features of DPM Mechanical Recol Gens 1-3 Reduction System Faster follow up shots. Improved firing speed. Slide and frame protection. Elimination of jams. Significant recoil reduction. Better double-tap concentration. Better control and greater accuracy. Package Contents: DPM Mechanical Recol Gens 1-3 Reduction System What firearm models does the manufacturer say DPM Mechanical Recol Gens 1-3 Reduction System is compatible with? The manufacturer says that DPM Mechanical Recol Gens 1-3 Reduction System is compatible with Glock 31 Glock 37 Glock 17 Glock 22 Glock 19 Glock 23 Glock 32 Glock 38 Glock 25 Glock 20 Glock 21 Glock 21SF Glock 17L Glock 34 Glock 35 Glock 24CDPM MS-GL/4: Mechanical Recol Gens 1-3 Reduction System Glock 17L/24C/34/35 Stainless