A
switchblade (also known as an
automatic knife,
pushbutton knife,
ejector knife,
switch,
Sprenger,
Springer,
flick knife, or
flick blade) is a type of
knife with a folding or sliding
blade contained in the handle which is opened automatically by a
spring when a
button,
lever, or
switch on the handle or bolster is activated. Most switchblade designs incorporate a locking blade, in which the blade is locked against closure when the spring extends the blade to the fully opened position. The blade is unlocked by manually operating a mechanism that unlocks the blade and allows it to be folded and locked in the closed position.