Spring assisted folders help whip out your blade quickly and easily when you need them. They are especially handy if you need to use your knife one-handed. Spring Assisted Knives are different from Switchblades; they are legal in all 50 states (though there are a few cities with bans on them like New York). A Spring Assisted knife requires the user to begin opening the blade manually, touching the blade directly just like any other folding knife. Once the blade is pushed past the retaining resistance, the blade springs out to the open position. A switchblade on the other hand does not have the user touch the blade at all, and instead the knife is activated and deployed with a switch or a button location on the handle. There are still some legal restrictions on switchblades in a number of different states and cities. Because there are so few legal restrictions on Spring Assisted Knives they have become extremely popular. They do rely on a spring that will give out eventually, but most knife brands will replace the spring in your knife for you.