Secret service trainings and ideas

 Silent locking pocket knives. -Thumbstud knives -Switch blade knives Without a click, when it locks into place. Maybe with a material which will dampen the clicking noise to near zero decibells. And a bigger flipper is very important then, for safety.

Silent, locking switchblades and folding knives. So there's no click when the knife locks in to place and should stay in place, unless closing it again according to the delocking mechanism. Stealth, locking folding knives. (idea)