New CP O-Ring For Chicago Pneumatic Air Riveter Tool Models, Part # 8940167712. Please feel free to let us know if you have any questions. At Piedmont Tool we understand that time is money and your tools help you make money faster, so we strive to get your item shipped quickly to minimize your downtime. Thanks and let us know if you need any other parts we may not have listed. Chicago Pneumatic CP9884 (6151979884) Air Riveter