Zaffiri Precision UPK, Upper Parts Kit, For Glock 17/34 Gen 4, Includes Firing Pin and Spring, Firing Pin Spacer Sleeve, Firing Pin Channel Liner, Spring Cups, Safety Plunger and Spring, Extractor, Extractor Depressor Plunger Assembly, Slide Recoil Cover Plate, Guide Rod 17.34.4.UPK These fit Glock 17 and 34 - Gen 4. These are great for completing your custom slide. All parts are from US manufacturer. All Parts are made to the highest tolerance to the original specification.