Nylon insert flange lock nut:carbon steel (silverprimary color) / carbon steel (black zinc-plated). Hex nut:304 stainless steel / 8.8 class steel (black). Flange serrated nut: 201 stainless steel. Nylon insert lock nut:304 stainless steel / 201 stainless steel / carbon steel (black zinc-plated).
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