Wanted (older model) Oxygen Valve

I'm on the hunt for a functional older model oxygen valve that is compatible with older model steel oxygen cylinders and DIN tread regulators on the other side. The one in the sample image is unrepairable. With more modern oxy systems on the market they gradually get replaced and disappear. A guide line in regards to the fitting dimensions; the cylinder side has a tapered tread starting around 17mm going to 19mm, the regulator DIN tread is 26.4mm which fits a Mountain High DIN-477-9 regulator. Maybe someone has a working oxygen valve sitting on a shelve or a corner? Many thanks, Joachim.