Aluminum Covered Purple Spring Assist Knife. The knife makes an excellent EDC, with a 3.75 inch 3CR13 stainless steel blade attached to the 5-inch Purple aluminum coated stainless steel handle. When the knife is in the closed position, the blade is held in place by means of torsion springs; as the user applies manual pressure to the flipper to open the knife, mechanisms such as the torsion spring moves along a track in the liner and rapidly rotates the blade into the open and locked position. Features built-in flipper, lanyard loops, pocket clip, and Purple aluminum handle.