DPM Sig Sauer P320 Axg Legion 3.9in Ported Slide Mechanical Recoil Reduction System Slide 4.7in. The longer spring (more coils) is stronger and has a heavier pound rating than the shorter spring. The plugs because of the different length change the total force of the recoil system (slide full open position). As 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. The spring plug must always be installed when the DPM Recoil Rod and springs are used. Specifications for DPM Sig Sauer P320 Axg Legion 3.9in Ported Slide Mechanical Recoil Reduction System: Manufacturer: DPM Fabric/Material: Spring Steel Gun Make: SIG Sauer Gun Model: SIG Sauer P320 Features of DPM Sig Sauer P320 Axg Legion 3.9in Ported Slide Mechanical Recoil 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 Sig Sauer P320 Axg Legion 3.9in Ported Slide Mechanical Recoil Reduction System What firearm models does the manufacturer say DPM Sig Sauer P320 Axg Legion 3.9in Ported Slide Mechanical Recoil Reduction System is compatible with? The manufacturer says that DPM Sig Sauer P320 Axg Legion 3.9in Ported Slide Mechanical Recoil Reduction System is compatible with SIG Sauer P320DPM MS-SI/35: Sig Sauer P320 Axg Legion 3.9in Ported Slide Mechanical Recoil Reduction System Slide 4.7in