Keep your Dewalt Atomic Cordless Impact Driver running at peak performance with this comprehensive Collar Spring Steel Ball Replacement Kit. Compatible with Dewalt models DCF850B, DCF850, DCF845N, and DCF850N, this kit includes all the essential components needed to restore your tool's chuck assembly. Part numbers N864734, NA202231, and N921819 are covered in this all-in-one replacement assembly. The kit contains a knurled collar, steel ball, multiple springs, retaining rings, and O-rings — everything required for a thorough repair. Please note that the 14th accessory shown in the diagram is optional; if your drill anvil becomes stuck after extended use and cannot be pulled out, you may discard that component and discontinue its use. This replacement assembly is a practical solution for extending the life of your impact driver without the need for a costly full-tool replacement. Always refer to your tool's service diagram to ensure correct installation of each component.