5325-00-255-4615 (CL21A7591-252)
NSN 5325-00-255-4615 (NIIN 00-255-4615) is a retaining ring in Federal Supply Class 5325, Fastening Devices — a resilient metal item, circular or nearly circular, which is designed to be inserted into an internal or external groove and retained by its own spring action. Manufacturer part number CL21A7591-252 (Northrop Grumman Systems Corporation, CAGE 26916); also referenced as N5002-187MD (Rotor Clip Company, Inc.); MS16631-1187 (Military Standards).
Key specs: 47 to 52 rockwell c material hardness; full characteristics table below. NIIN assigned January 1960; DEMIL A (none required); export Schedule B 9606.10.0000.