Zaffiri Precision UPK, Upper Parts Kit, For Glock 19 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, Upgraded Stainless Steel Guide Rod 19.4.UPK Upper Parts Kit (UPK) for Glock 19 - 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.