Centennial Defense Systems MOD4 Stainless Steel Guide Rod Assembly for Gen 1-3 Glock 17 Black - Coated Rod Button Head Allen Screw 20lb Spring. This eliminates guide rod flex and ensures it will not chip crack or break like plastic guide rods providing a lifetime of reliable service. Flat wound recoil springs are manufactured of certified aerospace spec materials heat treated shot peened and stress relieved to maximize durability. The screw tip is easily removed to allow the user to change spring weights and fine tune the recoil spring to the ammunition of choice. Specifications for Centennial Defense Systems MOD4 Stainless Steel Guide Rod Assembly for Gen 1-3 Glock 17 w/Button Head Allen Screw: Manufacturer: Centennial Defense Systems Fabric/Material: Stainless Steel Gun Make: Glock Gun Model: Glock 17 Model Generation: 3 2 1 Package Contents: Centennial Defense Systems MOD4 Stainless Steel Guide Rod Assembly for Gen 1-3 Glock 17 w/Button Head Allen Screw What firearm models does the manufacturer say Centennial Defense Systems MOD4 Stainless Steel Guide Rod Assembly for Gen 1-3 Glock 17 w/Button Head Allen Screw is compatible with? The manufacturer suggests that Centennial Defense Systems MOD4 Stainless Steel Guide Rod Assembly for Gen 1-3 Glock 17 w/Button Head Allen Screw is compatible with Glock 17Centennial Defense Systems 10397: MOD4 Stainless Steel Guide Rod Assembly for Gen 1-3 Glock 17 Black - Coated Rod Button Head Allen Screw 20lb Spring