Instead of sourcing every part individually, the slide completion kit includes every part needed to assemble the internal workings of your slide, all designed to work together. Includes: Striker (firing pin) Spring, Extractor, Striker (firing pin) Safety Spring, Back Cover Plate, Extractor Depressor Plunger, RA Precision Striker (firing pin), Striker (firing pin) Spacer Sleeve, Depressor Plunger Spring, Striker (firing pin) Safety, Spring Loaded Bearing, Striker (firing pin) Spring Cups, Slide Channel Liner. Tighter tolerances than factory, Low-temperature vacuum PVD (Physical Vapor Deposition) coating, on select parts, creates a durable barrier against wear and tear, Select parts, CNC-machined from solid stainless steel billet, Individually hand inspected for accuracy. Brand Rival Arms Category Other Gun Parts Model Slide Completion Kit Finish Black PVD Color Black Firearm Fit Glock 21