The Zaf Upper Parts Kit (UPK) is specifically designed for Glock 17 Generation 4 pistols providing all necessary components to complete your custom slide build with US-manufactured quality.Zaf Upper Parts Kit for Glock 17 Gen 4US manufacturer with highest tolerance specificationsMade to original Glock specificationsGen 4 specific compatibility - not compatible with other generationsComplete kit for custom slide completionPerfect for gunsmiths custom builders and enthusiasts looking to complete their Glock 17 Gen 4 slide projects with precision-manufactured components that meet original factory standards.