Up for Buy-It-Now is a new old stock (without the box) control starting switch that was obtained from an old service garage.  There are no part numbers on the piece, but from research in my Delco Manuals, I believe this to be GM 1996085 and used on the following models and years:

1953 Nash...All
1954-1955 Nash Ambassador
1957 Nash Ambassador  w/ Automatic Transmission

1956-1957 Hudson Hornet

1957 Rambler...w/ Automatic Transmission

  As always, please refer to your own individual manuals to be certain this is the part you need before bidding as there is no Delco part number cast on the piece to confirm the application listed above.   The assembly is in brand new, never used condition and shows no indication of ever being mounted or installed.    The push button is free and the assembly has vacuum.  
  Please feel free to E-mail me questions.  International bidders are always welcome.  Thanks for looking!!!