Lock Washers Serrated External BZP M4

Serrated external lock washers in M4 size, finished with bright zinc plating (BZP) for corrosion resistance. These washers feature sharp serrations that bite into surfaces to prevent fastener loosening under vibration and movement. Ideal for securing bolts and screws in machinery, automotive applications, and general engineering work where reliable locking is essential. The BZP coating provides protection in most indoor and moderate outdoor environments.