Mtech Spring Assisted Knife 3.5in 3CR13 Stainless Steel Harpoon Point Steel Blade Aluminum Handle Green. The basic principle behind the assisted opening mechanism is that two or more movable locking levers are placed next to each other and the slot machined so that when the handles are pressed simultaneously the spring arms move and open the blades. After the blades open the spring forces close the latch and effectively lock the blades open. When closing the blades the spring activates the latch and moves the locking levers to the open or closed position where they then engage and lock the blades together. This knife is equipped with a slot machined aluminum handle and a stainless steel liner lock with the traditional lashing hole at the end of the handle for the optional scarecrow / pocket clip. Specifications for Mtech MT-A1129 3.5in Spring Assisted Knife: Manufacturer: Mtech Blade Length: 3.5 in Blade Material: 3Cr13 Serrated: Plain Overall Length: 8 in Handle Material: Aluminum Handle Length: 4.5 in Handle Color: Green Handle Finish: Anodized Design/Pattern: Military Shark Blade Finish: Steel Blade Shape: Spear Point Opening Method: Spring Assisted Additional Features: Clip Color: Green Package Contents: Mtech MT-A1129 3.5in Spring Assisted Knife Mtech MT-A1129GN: MT-A1129GN Spring Assisted Knife 3.5in 3CR13 Stainless Steel Harpoon Point Steel Blade Aluminum Handle Green