It is very hard to find a quality knife of that kind. Here in Italy those knives are very often made with cheap materials and poor manifacturing.
I can't see a real use for them, but to appear in a cheap gangster movie.
If you absolutely want one of them, look for one with a brand name on it (some time ago you could find FOX or Virginia), or from the towns of Scarperia or Maniago (Italy).
Very often there is the word "INOX" on the blade, meaning nothing but the blade is made of (cheap?) stainless steel.
I had one of them some years ago that couldn't lock well, and it could happen it could close on my finger or didn't stop when opened and "continued to open", going upwards.
Falcenberg