Leverlocks - Leverletto Switchblades. Lever lock switchblade knives incorporate a lever or paddle that folds flat against the knife which can be folded up and pressed to deploy the blade. The Leverletto is a design which incorporates the style of a classic Italian stiletto with the release of a lever lock knife. All Switchblades and stilettos are shown with average overall open length in inches. How to open a picklock knife is shown to the left.