radi(c)al_cam
Well-known
Additionally we should mention the not really scarce Braun Paxette rangefinder lenses having «M39x1mm pitch» — quite often offered as if they were lenses for Leica.
You can force it on a Leica, but: unless you have a certain extension ring, they're useless; and then they don't couple the Leica's rangefinder …
But to make it more complicated: some of the lensmakers who made Paxette lenses also made lenses for Leica with the correct Leica coupling and «Leica M39x26tpi pitch».
Hence perhaps the confusion, even renowned shops sometimes get it wrong in the items' descriptions.