Tunic button BJ 42

[PanzerVI]

Hello

During todays relic hunting on WW2 battle fronts I have encountered this button, marked B J 42.

Any idea which manufacturer had this code ? I searched my RZM but to no result. I'd be interested in a list of manufacturers because I have found shoulder tabs buttons, tunic buttons all marked and I'm trying to figure out who made them for the german Wehrmacht.

Thank you kindly

[PanzerVI]

I found out eventually : Niebecker& Schumacher Metallwarenfabrik Iserlohn(NW)