Upgrade your current Gen 1-3 Glock 17 or complete a new build using our complete upper parts kit. Specifications for Centennial Defense Systems MOD5 Upper Parts Kit for Gen 1-3 Glock 17 w/Flat Face Button Head 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 MOD5 Upper Parts Kit for Gen 1-3 Glock 17 w/Flat Face Button Head Screw Stainless Steel Guide Rod Assembly (Allen Screw) Stainless Steel Channel Liner Stainless Steel Firing Pin Firing Pin Spring Firing Pin Spacer Sleeve Spring Cups (2) Stainless Steel Firing Pin Safety Firing Pin Safety Spring Stainless Steel Extractor Stainless Steel Extractor Depressor Plunger Extractor Depressor Plunger Spring Spring-Loaded Bearing Aluminum Slide Cover Plate