That's true Houston, and these replacements are usually seen being made from steel and can be detected by a magnet when one is inspecting a nickel chain. But the beveled connectors on the Type X chain are nickel, matched in color/ patina, and consistant with the other connectors,when one of these Type X chains are found unaltered or repaired. Plus the Type X chain has a different Rune Link and a different Skull link than the other two types of chains. There definitely has to be at least a third firm that made these assemblies and perhaps more.
