A spring assisted knife, also known as an assisted opening knife, is a type of
folding knife. It has a built-in spring that helps open the blade. The user begins to open it, and then the spring takes over and completes the action. This makes the blade open fast and smooth. It is different from an automatic knife, or switchblade. An automatic knife opens all the way with just a button.To open a spring assisted knife, the user must first press a thumb stud or flipper tab. When the blade gets halfway open, the spring takes over and snaps it open. This knife can be used with one hand and is allowed in many U.S. states.. That makes it a popular choice for
everyday carry (EDC), tactical use, and outdoor activities.