3/8"-24 Serrated Flange Lock Nut - Plated 3/8"-24 serrated flange lock nut - plated SFN3824 $0.129/ea
5/16"-24 Serrated Flange Lock Nut - Plated 5/16"-24 serrated flange lock nut - plated SFN51624 $0.087/ea