5/16"-18 Serrated Flange Lock Nut - Plated 5/16"-18 serrated flange lock nut - plated SFN51618 $0.057/ea
5/16"-18 K-Lock (KEPS) Nuts - Plated 5/16"-18 keps (k-lock) ext.Tooth lock nut plated KLN51618 $0.084/ea