FOUND THIS IN AN ANTIQUE SHOP TODAY FOR $ 5. THE PLUNGER WAS REMOVED BEFORE THE GLASS WAS SET UP OBLITERATING THE SCREWS. IT WAS NEVER PUT IN SERVICE AS THERE IS NO WAY IT WOULD FIT ON A PIN. SO IT IS SAFE TO SAY IT WAS PROBABLY REMOVED FROM THE FACTORY BY ONE OF THE WORKERS BACK IN 1946. A FRIEND OF MINE FOUND A CD 155 WITH THE SAME PROBLEM A YEAR OR SO BACK. SO I KNOW THERE MUST BE SOME OF THESE OUT THERE. IF YOU HAVE ONE .PLEASE CONTACT ME. THANKS TO A FINE COLLECTOR FROM MILLVILLE N.J. THIS OCCURRED WHEN COMPRESSED AIR WAS FORCED INTO THE PIN HOLE WHEN THE INSULATOR WAS BEING MADE..