The Stiletto had a folding, automatic opening design, allowing the blade to be unfolded with the push of a button. The blade is relatively long, slender, and straight, tapering to a needle-like point and having a vestigal cross-guard (much like the medieval daggers of the same name). Most of these weapons had a locking device to keep the blade locked in the open position. Knives similar to the modern stiletto have existed in the late middle ages in Europe.
The stiletto was primarily for stabbing and thrusting, although it could also be used for cutting and slicing. The locking mechanism, combined with the blade's narrow, pointed blade, made it highly effective when thrusting, unlike most present-day switchblades. Gangsters would carry these small blades because they were easy to hide in their pockets.