I know there are different Caliber Thompson Sub-Machine Guns. I don't know which this is as I'm no expert. I don't even know if this is a Original one after WW1, but this is a Nice one. Since the Case is for a Violin or a Small Guitar all I can think of this as being a Chicago Typewriter. Very Nice one at that. My eyes can't focus on the writing, would anyone know what a Original one would go for. The last time I seen a original one was in Houston, TX at a International Gun Show in the very late 80's or very early 90's and it had a price tag of $10,500. I do remember that as I looked at it for quite awhile. Only If....