1/4"-20 Serrated Flange Lock Nut - Plated 1/4"-20 serrated flange lock nut - plated SFN1420 $0.039/ea
1/2"-13 Serrated Flange Lock Nut - Plated 1/2"-13 serrated flange lock nut - plated SFN1213 $0.204/ea