There seems to be a lot of mis-information on the internet regarding these knives. These knives are not German made, they are Italian. And they were not made in the 1930's, 40's, 50's. They were made in the 1960's after the switchblade act of 1958. Made as a legal one handed opening alternative knife to the switchblade. They came in various sizes and handle materials as well as various tang stamps. They also came in single or double ball models. Some were stamped "RAPID" on the bolster and some were not. Some were made to lock in the open position and some were not.

I currently have 3 different sizes of this knife listed. They all came to me many years ago direct from old stock in Italy. All were never used and never displayed. 

Vintage Italian one hand manual opening knife with genuine deer stag scales. This is a one hand opening knife made after the 1958 switchblade ban. This one was made to lock in the open position. Blade sits completely inside the handle when closed.  Stamped "Rostfrei" on the front tang. Overall open length is 8 1/2". In unused and unsharpened condition, never displayed! Features the original factory edge. Hard to find knife in this condition. Please contact me with any questions. eBay username is btackle. Money orders please.

Item # 80060