Smith & Wesson's M.A.G.I.C. spring assist technology is one of the best in the industry. This high performance assisted opener features a sharpened, 4034 stainless steel black tactical blade with an aggressive design. The aluminum handle has a steel liner and a slide safety lock. 3.4 in. blade. How are Spring Assist different from a Gravity Knife or Switchblade Knife? Gravity or Switch Blade knives feature a button, level, or other type of switch that releases a spring pressure to automatically open the blade. On a Spring Assist knife, there is no separate button or switch. Instead, you apply pressure to part of the blade to begin the opening process. This is usually a small bump of metal which sticks out under the knife, making it fast and comfortable to use. Once you press on that part of the blade, it automatically opens and locks into place. Since the action of opening the knife is started by pressing the blade metal, instead of a button or switch, it is considered to bypass the laws which ban Switch Blade knives.