In Lara Croft: Tomb Raider, the villain Powell uses a particular kind of OTF knife. I don't know if it's a single- or double-action, but it has this sort of "finger ring" on the side of it.
Is this an actual knife, or a custom prop for the movie? If it's based on an actual knife, does anyone know where I might find a similar one? I quite like the design.