Cold Steel Knives AD-15 3.5 inch Folding Knife - The AD-15 might be the most comfortable， user friendly， sub 4 inch tactical folder we've ever made! Modeled after Andrew Demko's patented original， it offers ambidextrous operation and opens and closes with one hand. The saber ground spear point blade comes with a false edge and includes jimping on the spine to assure great piercing ability and edge control when precision cutting is required. The AD-15's unique hybrid handle is what distinguishes it the most; because it features Andrew's famous Scorpion Lock. You see， the bottom portion of the handle has 3D-machined G-10 scales mated to steel liners， while the upper portion of the handle， called the "yoke" is crafted from a 3D-machined 6061 aluminum billet that includes an integral back spacer which conceals a strong compression spring. To open the knife， simply engage the thumb stud and watch the yoke rise up， until it falls snugly into a deep notch cut in the blade's tang. Held securely by constant pressure from the spring and， supported by the strength of one's grip， the Scorpion Lock is virtually immune from failure!